Nova (1974) s04e08 Episode Script
Secrets of the Sky Tombs
1 OR: They came to live in the highest place on earth.
They buried their dead even higher.
MAN: Check it out.
WOMAN: Check it out.
NARRATOR: Littered among the bones are stunning artifacts.
MAN: The part I hate the most is make a dumb move, you're done.
NARRATOR: Top technical climbers are needed to reach the early human remains.
People's heads.
MAN: People's heads, yes.
NARRATOR: Somehow, the ancient people adapted to the Himalayan extremes.
But life wasn't easy.
WOMAN: This might be the cause of death for this person.
It's hitting right here, kind of at the occipital temporal mastoid junction.
MAN: People are people.
There's always conflict and violence.
NARRATOR: Relics are unearthed from sacred death rituals.
MAN: This is how the vampire-killing firebrand came into being.
NARRATOR: Archaeologists are uncovering the "Secrets of the Sky Tombs," up next on NOVA.
Major fuNARRATOR: NOVA is prThe Himalayan mountains, Earth's tallest, pierce the clouds.
Called "the roof of the world," the terrain is so high, the air so thin, this was one of the last places on Earth humans came to inhabit.
Today, about 6,000 people eke out a living here, in a region called Upper Mustang.
Their villages are oases in a high-altitude desert.
Above several of the villages are caves carved by hand long ago.
Many are so hard to reach, no one has entered them in recent memory.
But for years, human bones have tumbled out of the caves-- tantalizing clues that ancient inhabitants of the Himalaya are buried here.
Who were these people? Where did they come from, and what drove them to populate such an extreme environment? An international team of scientists and climbers are mounting an expedition to explore the caves.
Himalayan alpinist Pete Athans has climbed Mount Everest seven times.
PETE ATHANS: I've been coming to Nepal now more than 35 years.
The type of skills that I bring to the table is the physical ability to get into the caves, getting our scientists into the caves, more importantly.
NARRATOR: Pete has assembled a team of scientists and the world's best climbers.
ATHANS: Is that pretty much above the big portal as far as you can tell? LIESL CLARK: He can probably make it in from there, but he might have to swing a little bit.
NARRATOR: There are over 10,000 caves here, and they've targeted the most promising.
This one? CLARK: You got it! NARRATOR: The climbers are working with archaeologist Mark Aldenderfer.
MARK ALDENDERFER: The big question that we're trying to solve with this project is, where did people come from that began to live here in these high Himalayas? What were their origins? When did they come here? NARRATOR: The task is enormous, made ever more difficult by the unforgiving altitude.
The river valley that runs through Upper Mustang is one of the only north-south passages through the Himalayas in Nepal.
It's an ancient trade route connecting India to the south with China's Tibetan Plateau to the north.
For centuries, Mustang served as a cultural crossroads between Tibet and the Indian subcontinent, yet managed to keep its ancient fortresses and pastoral identity hidden from foreign visitors until 1992.
The locals are skillful traders.
Their cash crop is goats.
What defines the people are their Buddhist beliefs and a traditional way of life.
Living at such high altitude is not easy.
Of the five babies born in one of Upper Mustang's villages in one year, only three survived.
à à Could Mustang's modern people be the descendants of those who are buried in the caves? Who were the mysterious people, and why did they carve these sky tombs? The team treks to one of the highest villages in the region, called Samdzong.
It's just ten kilometers from the Tibetan border.
To get there, they have to cross a mountain pass at 14,700 feet.
Pete's children have grown up in the Himalayas, coming to Nepal every year since they were toddlers.
Going up a pretty big pass.
NARRATOR: They're at an altitude where pilots in unpressurized planes must breathe supplemental oxygen.
Curse this.
NARRATOR: Low levels of oxygen can cause debilitating symptoms in people who don't live here.
(breathing heavily) NARRATOR: The expedition members are among the first foreigners in modern times to visit Samdzong, which means "earth fortress," named after a stronghold above the village, now a crumbling ruin.
(bell ringing) (men praying) To show respect for local traditions, the expedition holds a puja, a Buddhist offering to the mountain deities, before scouting cliffside caves in the area.
Pete's son, seven-year-old Finn, is the first to find a human bone below some caves.
He shows it to bioarchaelogist Jacqueline Eng.
Finn found this humerus of a human.
You can see it's a proximal humerus on the right.
Don't know what context this comes from-- maybe washed down from somewhere.
NARRATOR: Caves dot the rock face above them.
The cliffs have eroded over time, exposing the contents of the tombs, which were likely first accessed by shafts dug by early people from above.
CORY RICHARDS: We've rapped into two chambers that are connected, that have lots of what appear to be human remains, and animal as well.
As well as more bones on the outside.
NARRATOR: Pete will first map the bones and artifacts to provide context.
ATHANS: What we want to do is to quickly draw, label, and then number, and then get them down to the scientists so they can start to take a look at these things and give us an idea of what and whom they belong to.
NARRATOR: Human remains have been tumbling out of the cliffside graves for years.
Because the caves are swiftly eroding, this vertical dig for artifacts and bones qualifies as rescue archaeology.
There are ten cave tombs in all.
Although he has a fear of heights, Mark has to see the tombs himself to fully understand the site.
CLARK: Does it ever get easier? Uh-uh.
The part I hate the most is actually walking up that trail.
It's really narrow, and you just make a dumb move, you're done.
NARRATOR: Pete puts Mark on a double rappel, both ropes clipped into Pete's safety device so he can stop Mark if he falls.
It's a 200-foot cliff, with a 40-foot drop into the uppermost caves.
First, excess dirt from collapsed walls is removed from the caves.
Then the dirt is sifted to uncover the smallest artifacts.
Each haul bag holds as many as a hundred bones, about half an individual.
Mark believes the caves were carved out intentionally to entomb the dead.
ALDENDERFER: People carved these caves because this was their cultural pattern on how to deal with the dead.
You know, we Westerners often put ourselves in cemeteries.
These folks here created a different kind of cemetery, what I would call a communal tomb.
NARRATOR: The team finds thousands of bones.
They'll analyze each one to piece together the story of the unknown people.
Now the hard part begins-- doing the lab work.
NARRATOR: For Jacqueline Eng, studying bones is like reading the personal diaries of the dead.
I'm always a little bit in awe when I do get to handle human remains, because it's one of the last stories that these people can tell-- what they experienced in life.
"I died young, I had this infection," or, "I died peacefully.
" NARRATOR: Jacqueline determines that a minimum of 105 individuals were buried in the Samdzong cave tombs.
Later, carbon dating of the remains will show the people lived between 400 and 650 AD.
But there's something unusual about how the ancient people treated their dead.
Here's a couple of ALDENDERFER: Good God! That's a cut mark.
NARRATOR: Clear cut marks from a knife are evident on many of the bones.
In some instances, multiple cuts are found in one place.
This is not the distinctive pattern of cannibalism, but it indicates the Samdzong people were dismembering and defleshing their dead.
This bears some resemblance to the local funeral practices today-- the Buddhist ritual of sky burial.
When a villager dies here, they're not buried underground, but are offered in a high place to birds of prey to ensure the deceased do not return to their bodies.
CHARLES RAMBLE: At the present time, as soon as somebody dies, the first thing that the family will do is to break that person's back, because they have a visceral fear of the dead body becoming a rolang which is a term generally translated as "zombie.
" The idea is that a person dies, and his or her consciousness departs from the body, doesn't realize it's dead, sees the body there, and then tries to reinhabit it.
This is one of the reasons, they say, why they don't bury the dead, because they might rise again.
(man praying) NARRATOR: The flesh and even the bones are cut into small enough pieces for the vultures to consume.
But unlike the ancient bones preserved in the caves, this Buddhist sky burial is performed to ensure nothing of the body remains.
Its purpose is to give the dead a chance of being reincarnated, to live another life.
NARRATOR: Buddhism, with its custom of sky burials, is thought to have spread through this part of the Himalayas more than a century after the Samdzong people lived and died here.
ALDENDERFER: All right.
NARRATOR: Yet, an artifact found in one of the Samdzong tombs challenges this notion.
There are some interesting Buddhist-era remains in that that we did not expect whatsoever.
It's like a little plaque made out of clay.
And it's got a seated Buddha.
NARRATOR: A Buddha in a cave with human bones seems out of place.
ALDENDERFER: It's a very funny mixture.
they're still doing the defleshing, but yet they've got Buddhist elements with them.
Yeah.
Go figure.
NARRATOR: Why does a cave holding the defleshed bones of a people predating Buddhism by more than a century have an image of the Buddha in it? Early Buddhism and how it spread is really a big open question.
Nobody's really found clear and convincing evidence of their mortuary patterns.
So these findings are pretty exciting.
NARRATOR: This could be the earliest Buddhist relic ever found in the high Himalaya.
Look how fragile.
RAMBLE: You have this Buddhist artifact there, which seems to be much earlier than it ould be.
In theory it should be no older than the 7th century, but the archaeological evidence seems to suggest it is older.
So we have Buddhism on the edges of the Tibetan Plateau at least quite a long time before the official introduction of the religion into the area.
What you also have is evidence of a type of burial that precedes the Buddhist form of burial that took over in Tibet in the late 8th century.
So the fact that Buddhism is also present does indicate that we're at a transitional stage.
NARRATOR: It's possible Buddhism started earlier here than previously known, and people buried the bones of the dead after removing the flesh.
The rite perhaps foreshadowed the sky burial practice of today.
A forensic investigation of Samdzong's artifacts commences, to determine their possible origins.
One cave had a coffin-like bed inside.
Hmm, that's leather.
WOMAN: That's leather.
NARRATOR: Alongside the bed were the remains of a horse and some horsetack, suggesting the body was that of a prominent individual.
Rich artifacts like a large copper pot, bronze bracelets, iron daggers, and glass beads littered the grave.
Two mysterious pieces of metal were also found in the cave.
SUSAN: Wow! I really don't want to flatten it too much.
So, that look like a nose? CLEO: That kind of looks like an eye.
ALDENFERDER: We have two masks.
NARRATOR: They are death masks, and there's even a third one.
CLEO (whispering): Please don't break! ALDENFERDER: Here we go.
Check it out.
This guy's got more color.
NARRATOR: They need to determine what metals the masks are composed of and where they were made.
So a sample is sent to University College London for analysis by metallurgist Giovanni Massa.
He found there are two layers of precious metals in the masks.
GIOVANNI MASSA: What you see in this picture is a section of one of the masks.
and you can clearly see there are two different colors-- the front, in yellow color, which is the gold layer, and the silver, which is the back of the mask.
The technique that they used was hammer welding.
NARRATOR: There are no gold and silver deposits to be found nearby, and the technology needed to hammer gold and silver into death masks indicates the craftsperson who created them was highly skilled.
MASSA: What is actually very striking is the thinness of the mask-- around 50 microns, which is less than the thickness of a human hair.
In fact, to make the artifact, you won't need a lot of material.
You would need a sphere of about this size for the silver layer and an even less amount of gold.
NARRATOR: Pinholes can be detected on the outer rim of the mask.
MASSA: The pinholes were used to attach the mask to something else in order to actually have it stable on the face of the person.
I think the mask was actually sewn onto a fabric and the glass beads were sewn onto that fabric as well, and formed fairly elaborate headdress.
The mask covered the face, the fabric covered the head, and then the glass beads were covering that fabric itself, draped down over the shoulders onto the chest.
Must've been absolutely spectacular.
MASSA: What you see is an incredibly rich collection of artifacts.
Pretty much any alloy you could think of.
One of the medallions found is stylistically completely different from the rest of the collection.
You have the copper vessels that are just hammered surfaces, very simple.
You have the brass bangles that have very simple decorations.
And then you have this beautiful medallion.
All this shows that these people were connected to a network.
NARRATOR: By the time the Samdzong people were adorning their dead with gold masks, traders from Asia were exchanging goods with Europeans along an ancient trade route to the north called the Silk Road.
The cave-buried people might have come from the vast area we know today as China.
Or are these simply trade goods from the north? They need more evidence.
A single piece of cloth found in one of the caves could provide a clue.
Textile expert Margarita Gleba at University College London made a discovery using a scanning electron microscope that can magnify specimens up to 30,000 times.
MARGARITA GLEBA: This textile seemed to be made in what we call plain weave, or also known as tabby.
Tabby.
And that is the simplest type of weave you can create on a loom.
So it's one over, one under.
A curious thing with this particular sample is that all the fibers appear to be parallel to each other, but they're not twisted in any way.
NARRATOR: Most thread or yarn is produced by spinning short fibers, like this wool.
The twisting action gathers them together into a single long thread.
The only fiber that allows you to produce a thread without a specific twist is silk.
And the reason for that is that silk fibers are extremely long.
A single silk fiber, when unrolled directly from a silk cocoon, can reach up to two kilometers in length.
We can be quite sure that we are dealing with Chinese silk.
NARRATOR: Since the cloth found in the cave is silk, could this suggest the people came from China? The Samdzong remains only date to 400 AD.
The earliest known pottery in the region dates back to 800 BC, so there must have been people earlier than Samdzong.
And Mark wants to find them.
Today's archaeological objective is a cave at 10,000 feet known as Rhi Rhi.
It's a few hours' journey from the nearest town.
A complete kitchen, cook staff, climbing gear, tents, and food make up the loads which will have to be carried across a river called the Kali Ghandaki.
This is the deepest river gorge in the world, carved by the glacial meltwaters of some of the world's highest mountains.
Any other time of the year, the river runs so high here it's impassable.
With anchors firmly in place, Pete can rappel down a slope most climbers would avoid altogether.
Pete leads another double rappel with Mark.
ALDENDERFER: Hold on a sec.
ATHANS: Okay, you can just keep lowering yourself in till you're seated at the edge.
There you go.
We're good.
NARRATOR: It doesn't take long for them to find what they're looking for.
ALDENDERFER: These are all human bones that we're coming up with at the moment.
NARRATOR: A hand-carved wooden peg is among the first artifacts found.
It looks like one of those little daggers.
That's a really cool thing.
NARRATOR: What Mark really wants to find is black pottery that would suggest the burials are around 3,000 years old.
This is some good pottery.
Oh, look, yeah, there's blackware, too, wow.
Very nice.
Thank you, Satish.
NARRATOR: The pots are definitely black, with characteristic thick handles.
Carbon dating later confirms the burials are 2,800 years old, among the earliest ever found in the Himalayas.
Mark unearths a deep hole in the cave, where the early people were entombed.
ALDENDERFER: What we're looking at is a pit.
And then at some time they just bring them up here, open up the pit, and put them in, and then go back.
NARRATOR: They ultimately find the bones of about five people.
Am I good? Yep, you're good.
Okay, nice and easy.
Okay, I'm with you.
NARRATOR: For the local people, finding human bones can be unsettling, because they believe in completely eliminating the remains of a corpse after death.
Molecular anthropologist Christina Warinner notices that the bones have been disturbed and altered by visitors to the cave.
A group went in much, much later, and they applied ochre to the remains.
Ochre is this mineral pigment that's naturally occurring.
This red ochre has been rubbed on some of the bones, and in other cases sprinkled on them.
We know that it was applied after death, because we find it both on the exterior of the skeletal remains and also on interior surfaces.
So it must've been applied after the body had already decomposed.
NARRATOR: It's possible this was done by Buddhists, long after the initial burials.
So they didn't just ignore them or remove them, but actually actively engaged with them.
That's very unusual for this region.
NARRATOR: Another find from the cave supports this theory.
Mixed in with the bones, and broken into pieces, was a one-foot-square ceramic object, marked with strange engravings.
ALDENDERFER: If you look carefully at the surface, you see little daggers.
The use of these daggers like this is usually some kind of exorcism that's taking place to get rid of some sort of evil or maleficent spirit that happens to inhabit a place.
RAMBLE: "Dagger" describes the object that's called in Tibetan phurba.
A stake, basically.
And it's like any spike, the fundamental purpose is to hold something down, to stab it ritually and make sure it stays down.
NARRATOR: Mark believes the dagger object was left by later visitors to the cave, probably early Buddhists performing an exorcism in reaction to finding the bones.
ALDENDERFER: They enter these sites at some time in the past after the people have been buried in them.
They encounter the bones, and then they become frightened by them.
NARRATOR: If this interpretation is right, the daggers symbolically hold down the bones, like stakes, to prevent them from becoming reanimated.
The remains of the original occupants of the cave are from some of the earliest people yet found.
Mark wants to figure out where they came from.
For years, scientists believed these people migrated from the south, what is now India, because it was much more populated than the Tibetan Plateau and the lands to the north, now China.
A discovery in the early 1990s seemed to confirm the link to India.
In a cave complex in Mustang called Mebrak, German and Nepali archaeologists discovered the Himalaya's first mummies, naturally preserved by cold and dry conditions.
Carbon dating placed the 42 individuals as far back as 400 BC.
Since their discovery, the mummies have been stored in Kathmandu, until Mark received permission to examine the remains.
There's still a little bit of flesh on it.
You got that right.
NARRATOR: Some are still intact, like this mummified two-month-old baby.
Some of the bodies were found on wooden bunk-like beds, in a fetal position, ankles and wrists bound together with cloth.
No other burials like this have ever been seen in the Himalayas.
The artifacts look like they originate from the south, from what is now India, and include ornamental gourds, carved wood, a bamboo flute, and even glass beads.
India has been making glass for over 3,000 years.
This suggests the early people of the Himalaya could've come from India.
But it's not that simple.
Each cave burial the team uncovers in Mustang is different from the others.
Some are defleshed, some buried in pits, and others found on bunk beds.
There are influences from a number of regions, so the settlers could have been from different cultures across Asia.
There's a mystery here that can't be solved by examining artifacts alone.
CHRISTINA WARINNER: Many people proposed different hypotheses about where the people initially came from who colonized the Himalayan mountains.
But none of these lines of evidence was conclusive.
What we really needed was DNA from those first people in order to solve that problem.
NARRATOR: DNA is the double helix strands of chemicals in our cells that carry our genetic information and can reveal what we've inherited from our ancestors.
If Mark can procure DNA from the cave burials, he can find clues to their origins.
Upper molar two.
NARRATOR: A tooth's enamel is the hardest tissue we have.
It can protect the DNA preserved within the tooth for thousands of years.
Mark extracts teeth from the Mebrak mummies to add to his samples from the other caves.
ALDENDERFER: This one was very hard because it has much flesh keeping it together.
NARRATOR: For the teeth that are difficult to extract, he plays dentist to the dead and uses a rotary tool to free the tooth from the 2,300 year-old mandible.
The teeth go to Christina Warinner's lab at the University of Oklahoma.
It's a highly sterile workplace, built to protect ancient samples from the modern DNA that surrounds us.
WARINNER: There is DNA everywhere.
Every time you cough or sneeze, you're putting DNA into the air.
So if we want to be able to recover this very ancient and degraded material, we have to get rid of all of that extraneous DNA as much as possible.
So we conduct this work in special laboratories that have highly filtered air.
We have ultraviolet radiation built into the ceiling to sterilize the room in between uses, and we wear these Tyvek suits, which help keep our DNA in.
Most people, when they see them, they're used to seeing them in context of people in epidemics trying to protect themselves from disease.
We wear them for the reverse reason.
We're trying to protect our samples from our DNA.
We clean the teeth with bleach to remove and destroy any DNA on the surface.
In a way, it's almost like getting a very belated dental cleaning.
We use an abrasive tool to remove the outer layer, to really scrape off these contaminants.
And then we use ultraviolet radiation that causes damage in any DNA that's still remaining on the surface.
We can then liberate the DNA from the tooth itself.
NARRATOR: Tina's meticulous cleaning methods pay off.
She's found some of the best-preserved ancient DNA ever sequenced.
WARINNER: That is extraordinary, and likely resulted because the region is so cold and dry.
NARRATOR: 100 milligrams of tooth material, about the size of a pea, is all that's needed to fully sequence a single human genome-- the genetic blueprint unique to each of us that contains traces of our ancestors' DNA.
WARINNER: We can take these pieces of DNA.
From that, we can painstakingly reconstruct the genome of that person, and learn all sorts of things about them-- what they looked like, if they're male or female.
We can learn where their ancestors came from.
NARRATOR: Geneticists can find out clues to our origins by looking closely at small variations in our DNA and comparing them to other groups.
Population geneticist Anna Di Rienzo found that the genomes of all the samples collected in Mustang, even those from different caves, are very similar.
ANNA DI RIENZO: One of the major findings of our study is that the gene pool of these populations hasn't changed in a major way over the period of time that we have sampled, which is roughly 3,000 years.
NARRATOR: After comparing the samples from the cave people with each other, Anna then compared the genomes with different present-day populations around the world.
She's looking at small sections of their DNA for similarities and differences in the order of DNA's four chemical bases, abbreviated as A, C, T, and G.
We can ask with this analysis, "Who are the populations that are closest genetically to our samples?" NARRATOR: Surprisingly, there was no match with people from any part of India today.
The results indicated the Himalayan peoples are most closely related to East Asians, including today's Japanese, Han Chinese, Tibetans, and the Sherpas, who live near Mount Everest.
So the earliest Himalayan people came from the north, from East Asia and the Tibetan Plateau.
Although their burial customs differed from one group to another, and some had artifacts from India, and lived at different times, genetically, all the cave people were very close.
WARINNER: The genetics were incredibly stable through time.
This was fascinating to us because we saw big changes.
For example, between the Mebrak and the Samdzong period, we suddenly see defleshing.
That's a new thing, that's a religious change, and yet we don't see any change in the underlying genetics of the population.
NARRATOR: But researchers have spotted one genetic change specific to high-altitude peoples of the Himalaya.
It's an ancient mutation, or gene variation, a change in the order of the chemical bases-- the As, Ts, Cs and Gs that make up the gene.
The variant prevents people from getting sick at high altitude where the available oxygen is low.
WARINNER: There are a few places in the genome, a few traits in which we have experienced very recent evolution.
So one of these would be the adaptation to high altitude.
There's only a handful of these genes that are very, very recently undergoing selection, and this is one of them.
NARRATOR: Most of the Himalayan people that live here now have this variant.
The team wants to know if the ancient people buried in the caves also had this mutated version of the gene.
To gather even more DNA samples, the team heads to another burial site, in a region called Nar-Phu, where there are reportedly hundreds of bones.
Although it's only 30 miles away as the crow flies due east, getting there takes three days of driving and another three days on foot.
It'll take ten hours to hike to 12,000 feet in a day, a rapid 4,000-foot gain in elevation-- not enough time for most people to acclimatize, or adjust, to the altitude.
ATHANS: Now, you'll see as we're walking uphill, steadily gaining elevation, we have to breathe a lot heavier.
Might just feel like our performance is really down.
Now, a lot of the locals don't really feel that, because they have that special makeup in their DNA, and it allows them to acclimatize very quickly.
Meanwhile we're out of breath.
We're definitely feeling a lack of performance.
We might feel like we have a little bit of a headache, a little dizziness.
NARRATOR: There's about 35% less oxygen available here than at sea level, so the team keeps track of how much oxygen is getting into their bloodstream as their bodies adapt.
We're at Meta, which is at about 11,700 feet, and we're just going to be checking the level of oxygen concentration in the bloodstream with a pulse oximeter.
The lower number is the pulse rate, and the upper number is the percentage of oxygen that's being carried by the blood.
NARRATOR: When we breathe, oxygen enters our bloodstream and provides our cells the fuel they need to carry out their jobs.
At sea level, a healthy person should have at least 95% oxygen saturating their blood cells.
But at 12,000 feet, lowlanders who first arrive will only have between 80 and 90%.
ATHANS: There is about an 82% carrying capacity of O2, percentage of oxygen in the bloodstream currently.
And their pulse is at about 108, 109.
These are fairly common numbers, actually, for arrival at altitude.
For unacclimatized folks.
For an unacclimatized person.
Yeah.
NARRATOR: If Mark were at sea level, 82% would be a low blood oxygen saturation, called hypoxia, and he'd be given bottled oxygen to breathe.
But at altitude, this figure is normal.
In contrast, Himalayan people can tolerate low levels of oxygen, thanks to a genetic trait.
ALDENDERFER: Somebody who lives at altitude that's got the appropriate genetic adaptations, I'd expect their pulse rate to be lower.
I'd also expect their oxygen saturation to be significantly higher than folks like me.
I guess we'll test that now.
Temba, where were you born? I was born in the Everest region, which is elevation about 12,600 feet.
My expectation is that Temba will have a relatively low pulse rate, and he'll also have a relatively high oxygen saturation in his blood, because he's adapted to high elevation life genetically.
Your saturation is what? I can't see it very well.
92, 91.
And his pulse rate is 78.
You know, pretty typical for folks that are adapted to this kind of life.
NARRATOR: If most of the people living here today have this genetic variant, the question is, when and where did this adaptation begin to appear? The team moves ever higher into the cold and arid alpine zone at 13,000 feet.
It's a wonder people came to settle here at all.
The villages are abandoned as locals have gone to higher pastures for foraging.
Life is hard here, which is why the Himalayas were settled so late.
ALDENDERFER: If you look at the pattern of human migration over the last two million years, mountains are one of the last places on the planet to in fact be occupied.
Deserts come earlier.
Polar extremes, like around the Arctic Circle, come somewhat earlier as well.
Mountains come somewhat later.
These are difficult places for people to live.
NARRATOR: They've reached their destination of Kyang.
The village feels like a ghost town.
There's really nobody around.
I walked through just trying to talk with some people, but it didn't look like I mean, there were a few donkey people just around the corner, but they left about 15, 20 minutes ago.
NARRATOR: These are the same pastures the early inhabitants used for their animals thousands of years ago.
ALDENDERFER: Somebody lived here some long time ago, built the site, and buried their dead somewhere around here on these relatively fertile pieces of ground surrounded by these incredible vertical environments.
We will have to find out what the dates are, and if there's any associated artifacts that give us a sense of what this group of people might be related to.
Because right now they're essentially unknown to us, except for the fact that they exist.
NARRATOR: The team is anxious to see if Pete can get inside the cave.
FINN CLARK: We can watch with the GoPro what Dad's doing, filming, on here live.
NARRATOR: About 800 vertical feet above the village is the naturally occurring cave with manmade walls stacked above it.
Work our way up, like from the right, up and around the cleft.
NARRATOR: Pete's objective is to get safely inside to photograph the interior.
ATHANS: We're at the base of the big crack now.
It's just that it's exposed, and there's a lot of loose rock stacked up on the ledges.
If you grab the wrong handhold or foothold you could send a big rock down or you could fall.
NARRATOR: Pete free-climbs the large crack leading deep into the cave.
He'll place an anchor above him for a safety rope if he falls.
ATHANS: Going up into the cleft and way back into the dark wearing a respirator mask and a headlamp, it can be very narrow.
I can certainly get very claustrophobic moving in there.
It's very dusty inside.
There's a lot of remains from birds and bats and every manner of rodent in there.
You're just inching your way up through this crevice, and then you enter this very spacious bone room.
It was very much crypt-like.
ATHANS (on walkie-talkie): Hey Mark, you guys copy? Yes, we copy, Pete.
I have a couple of jaws here, couple ephemera, and then a few other human pieces.
A piece of wood that's pretty interesting that are all in a bag right here we'll collect on the way down, break.
NARRATOR: The climb is too technical for the scientists to get inside.
So, Pete maps out sections of the cave on a grid, and all bones and artifacts are bagged according to their location.
ATHANS: The process with the grid that we're lining out is really just to try to give the archaeologists an idea of where in the cave these materials were actually taken from.
NARRATOR: The original burials have been disturbed, most likely by looters looking for valuable funerary goods.
ATHANS: There's a real scattering of materials.
It looks like someone had actually been doing some digging right down in this area to my left.
So we're looking at a context that's more disturbed than I had anticipated.
NARRATOR: It takes three days to fully excavate every bone and artifact from the cave.
ALDENDERFER: Okay, I've got the bag, if you guys pull.
NARRATOR: The next step is to look for signs of death rituals.
People's heads.
People's heads, yes.
NARRATOR: The presence of animal bones suggests they were sacrificed to bury with their human owners.
ALDENDERFER: This is a very common pattern in this part of the world, is to inter the dead with domesticated animals of one kind or another.
Here in Kyang the only ones that we've seen so far are sheep or goat.
RAMBLE: If you find animals in a grave like that, there's got to be a reason for it.
It's most likely that the animals were sacrificed and placed with the dead person for one of two reasons-- either to be food in the next life, to constitute part of his or her herd, or as the animal that guided the dead in the afterworld.
(collar bells ringing) NARRATOR: Every scrap of evidence is analyzed.
ALDENDERFER: It's definitely been imprinted on there somehow.
Good eye, Finn.
I bet if we wet it in water Oh yeah, check it out.
There it is.
Can you see it more clearly? Very nice artefact.
NARRATOR: It's a simple bamboo stick, but the woven pattern on it suggests it was once part of a basket.
Later, carbon dating reveals the people of Kyang lived around 200 BC-- the same time as the Mebrak mummies.
Their artifacts appear to be locally made, indicating the people were self sufficient and lived off the land.
The bamboo and wood could've come from nearby.
This is a very nice wooden bowl.
Soft wood.
It has a really lovely little base on it that's been made, and it imitates a bowl that's been made on a wheel.
So it's been carved to look like that.
NARRATOR: Jacqueline determines 23 people were buried in the Kyang cave, with no cut marks, and the presence of flesh on the joints suggests they were buried whole.
But the ages of the dead are surprising.
ENG: Several of these individuals were younger than 20.
Several of the adult remains are also younger adults, so below the age of 30, 35, and that suggests that people did die of something that shortened their lives.
Could be starvation, could be an infectious disease that, you know, moved really rapidly.
NARRATOR: An enigmatic object found in the cave hints at ritual practices that may be connected to these premature deaths.
One of the most interesting things we found during this work here at Kyang is this special stick.
You can see it's well-carved.
It's thin at the bottom, widens out.
Clearly it's been meant to either be put in the earth or maybe in a socket of some kind.
The first thing that jumps out when you look at this under the microscope that we have here in the field is those are little tiny pebbles that have been placed inside little tiny divots.
And the divots are holding glue, some kind of cement that hold these things in place.
But if you look at this image, it's the image of a person.
What I really think this person is doing is holding something we found in the archaeological site, what I've been calling fire sticks.
They're little sticks.
They might be four or five inches long, and usually one end is burned.
You can see the wavy or sinuous line, which I would interpret as smoke coming out of the end of that firestick.
NARRATOR: Cultural artifacts open a window on a people's long-vanished beliefs.
The humanoid figure on the stick is so unusual, Mark travels to France to see if anthropologist Charles Ramble can make sense of it.
Charles specializes in the ritual practices of Himalayan peoples.
What's the material? This is not just discoloration from water or something? ALDENDERFER: No, not at all.
That's actually what they've done to highlight, they've ground up some dark stone into very fine particles, and then literally pushed it into the outline of this to kind of emphasize and bring out the contrast.
So all this was intended.
All this was very much intended.
RAMBLE: (reading Tibetan text) NARRATOR: Charles has recently discovered an ancient text that describes a death ritual using sticks called firebrands, much like the ones Mark found.
RAMBLE: Tibetans believed that people died because their souls were taken away by death demons.
And these are known variously as shi or as shay.
Shi is commonly translated as "vampire.
" And rituals had to be performed afterwards in order to separate the soul from the demons who had taken it.
"I am Taklamembar, and this is how "the vampire-killing firebrand, the emanation of my mind, "came into being.
"The demon of bad death among males was killed "with the firebrands.
"The demoness of bad death among women was killed with the firebrands.
" There is one text-- its title translates as "The Origin Tale of the Firebrands for Killing Vampires.
" These firebrands in this text are being used as a means of killing vampires, and vampires are the agents that are responsible for death.
They are serial killers.
So if people of a certain age between 20 and 30 die in a series, that's the effect of vampires.
So the vampires are something that steal vitality, and eventually life.
And they latch themselves onto a family, and they will continue to affect that family until they are got rid of.
NARRATOR: This may explain why the firestick was found in the Kyang cave with young adults who died prematurely.
RAMBLE: It's unusual that we can find textual evidence to support archaeological evidence.
"The killing of vampires with the firebrand is over.
"May there be good fortune, good luck, blessings, and virtue.
" Stakes of this sort are very ancient.
They've been found in many parts of central Tibet, and also at the foot of the Great Wall.
And they date back to the third century BC.
NARRATOR: The discovery of stick effigies at the foot of China's Great Wall is another piece of evidence confirming these people could've come from there.
With DNA recovered from each cave population, the scientists can see, over a 3,000-year timespan, which of them was adapted to survive at altitude, and when the adaptation appeared.
DI RIENZO: An important feature of the study is that it provides ancient DNA samples and data from different time points in the past.
We can see how the data changes over time.
And this is what we call watching evolution in action.
NARRATOR: Anna finds that all of the people buried in the caves have the high altitude adaptation.
But the study of their DNA reveals there's a second adaptation that also enables people to live at altitude.
The earliest of the cave people have the first genetic variant, but the most recent burials, the Samdzong people, acquired a second variant.
Both variants are seen in the people of the region today.
The most surprising aspect of this variant is that scientists have seen it before.
In 2008, the tiny pinky bone of an extinct human ancestor was discovered in a cave in the Altai mountains of Siberia, called Denisova.
The 41,000-year-old pinky bone had just enough DNA in it to be sequenced.
The individual was female, young, and had that second adaptation.
DI RIENZO: This Denisovan population that had a relatively wide geographic distribution in Asia, maybe they already had adapted to high altitude.
That's part of the history that we would like to dissect.
NARRATOR: At some point in prehistory, Homo sapiens, our modern human species, must have mated with the now-extinct Denisovans.
It's likely the only way humans could have obtained the second high altitude gene adaptation.
We don't know exactly where the encounter between this Denisovan-like population and the modern human populations occurred.
It's possible that this mutation was present in the Denisovan-like population but was not advantageous, yet after the mixing between these two, and the modern human population moved to high altitude, it became advantageous.
NARRATOR: This important DNA variant, or allele, from an extinct human ancestor, is part of the genetic inheritance of Himalayan people today.
DI RIENZO: The finding was very exciting.
It's telling us something more than just the fact that modern humans and Denisovans mixed, but also that Denisovans gave modern humans an allele that allowed them to conquer this so-called Third Pole, and to adapt to these very harsh conditions of high altitude hypoxia.
NARRATOR: Genetics and the study of ancient DNA allow us to see modern human evolution in action.
WARINNER: This new ability that we have to actually sequence ancient genomes is teaching us so much we didn't know about human history and prehistory.
So, already, we're rewriting the storybook of humanity.
ENG: We're definitely still evolving.
The point at which we stop evolving is when we're an extinct species.
That's the end of evolution right there.
Those slight changes give us the ability to adapt to changing environmental conditions.
NARRATOR: Here in the Himalayas we can trace how we evolve over time.
That the people here can thrive at altitude shows just how adaptable we as a species can be.
We now know more about the early cave peoples' beliefs, and how they endured one of the toughest places on Earth.
And the knowledge gained by recovering ancient DNA and deciphering death rituals provides a clearer picture of the unique heritage of the mountain peoples who live at the roof of the world.
This NOVA program is available on DVD.
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They buried their dead even higher.
MAN: Check it out.
WOMAN: Check it out.
NARRATOR: Littered among the bones are stunning artifacts.
MAN: The part I hate the most is make a dumb move, you're done.
NARRATOR: Top technical climbers are needed to reach the early human remains.
People's heads.
MAN: People's heads, yes.
NARRATOR: Somehow, the ancient people adapted to the Himalayan extremes.
But life wasn't easy.
WOMAN: This might be the cause of death for this person.
It's hitting right here, kind of at the occipital temporal mastoid junction.
MAN: People are people.
There's always conflict and violence.
NARRATOR: Relics are unearthed from sacred death rituals.
MAN: This is how the vampire-killing firebrand came into being.
NARRATOR: Archaeologists are uncovering the "Secrets of the Sky Tombs," up next on NOVA.
Major fuNARRATOR: NOVA is prThe Himalayan mountains, Earth's tallest, pierce the clouds.
Called "the roof of the world," the terrain is so high, the air so thin, this was one of the last places on Earth humans came to inhabit.
Today, about 6,000 people eke out a living here, in a region called Upper Mustang.
Their villages are oases in a high-altitude desert.
Above several of the villages are caves carved by hand long ago.
Many are so hard to reach, no one has entered them in recent memory.
But for years, human bones have tumbled out of the caves-- tantalizing clues that ancient inhabitants of the Himalaya are buried here.
Who were these people? Where did they come from, and what drove them to populate such an extreme environment? An international team of scientists and climbers are mounting an expedition to explore the caves.
Himalayan alpinist Pete Athans has climbed Mount Everest seven times.
PETE ATHANS: I've been coming to Nepal now more than 35 years.
The type of skills that I bring to the table is the physical ability to get into the caves, getting our scientists into the caves, more importantly.
NARRATOR: Pete has assembled a team of scientists and the world's best climbers.
ATHANS: Is that pretty much above the big portal as far as you can tell? LIESL CLARK: He can probably make it in from there, but he might have to swing a little bit.
NARRATOR: There are over 10,000 caves here, and they've targeted the most promising.
This one? CLARK: You got it! NARRATOR: The climbers are working with archaeologist Mark Aldenderfer.
MARK ALDENDERFER: The big question that we're trying to solve with this project is, where did people come from that began to live here in these high Himalayas? What were their origins? When did they come here? NARRATOR: The task is enormous, made ever more difficult by the unforgiving altitude.
The river valley that runs through Upper Mustang is one of the only north-south passages through the Himalayas in Nepal.
It's an ancient trade route connecting India to the south with China's Tibetan Plateau to the north.
For centuries, Mustang served as a cultural crossroads between Tibet and the Indian subcontinent, yet managed to keep its ancient fortresses and pastoral identity hidden from foreign visitors until 1992.
The locals are skillful traders.
Their cash crop is goats.
What defines the people are their Buddhist beliefs and a traditional way of life.
Living at such high altitude is not easy.
Of the five babies born in one of Upper Mustang's villages in one year, only three survived.
à à Could Mustang's modern people be the descendants of those who are buried in the caves? Who were the mysterious people, and why did they carve these sky tombs? The team treks to one of the highest villages in the region, called Samdzong.
It's just ten kilometers from the Tibetan border.
To get there, they have to cross a mountain pass at 14,700 feet.
Pete's children have grown up in the Himalayas, coming to Nepal every year since they were toddlers.
Going up a pretty big pass.
NARRATOR: They're at an altitude where pilots in unpressurized planes must breathe supplemental oxygen.
Curse this.
NARRATOR: Low levels of oxygen can cause debilitating symptoms in people who don't live here.
(breathing heavily) NARRATOR: The expedition members are among the first foreigners in modern times to visit Samdzong, which means "earth fortress," named after a stronghold above the village, now a crumbling ruin.
(bell ringing) (men praying) To show respect for local traditions, the expedition holds a puja, a Buddhist offering to the mountain deities, before scouting cliffside caves in the area.
Pete's son, seven-year-old Finn, is the first to find a human bone below some caves.
He shows it to bioarchaelogist Jacqueline Eng.
Finn found this humerus of a human.
You can see it's a proximal humerus on the right.
Don't know what context this comes from-- maybe washed down from somewhere.
NARRATOR: Caves dot the rock face above them.
The cliffs have eroded over time, exposing the contents of the tombs, which were likely first accessed by shafts dug by early people from above.
CORY RICHARDS: We've rapped into two chambers that are connected, that have lots of what appear to be human remains, and animal as well.
As well as more bones on the outside.
NARRATOR: Pete will first map the bones and artifacts to provide context.
ATHANS: What we want to do is to quickly draw, label, and then number, and then get them down to the scientists so they can start to take a look at these things and give us an idea of what and whom they belong to.
NARRATOR: Human remains have been tumbling out of the cliffside graves for years.
Because the caves are swiftly eroding, this vertical dig for artifacts and bones qualifies as rescue archaeology.
There are ten cave tombs in all.
Although he has a fear of heights, Mark has to see the tombs himself to fully understand the site.
CLARK: Does it ever get easier? Uh-uh.
The part I hate the most is actually walking up that trail.
It's really narrow, and you just make a dumb move, you're done.
NARRATOR: Pete puts Mark on a double rappel, both ropes clipped into Pete's safety device so he can stop Mark if he falls.
It's a 200-foot cliff, with a 40-foot drop into the uppermost caves.
First, excess dirt from collapsed walls is removed from the caves.
Then the dirt is sifted to uncover the smallest artifacts.
Each haul bag holds as many as a hundred bones, about half an individual.
Mark believes the caves were carved out intentionally to entomb the dead.
ALDENDERFER: People carved these caves because this was their cultural pattern on how to deal with the dead.
You know, we Westerners often put ourselves in cemeteries.
These folks here created a different kind of cemetery, what I would call a communal tomb.
NARRATOR: The team finds thousands of bones.
They'll analyze each one to piece together the story of the unknown people.
Now the hard part begins-- doing the lab work.
NARRATOR: For Jacqueline Eng, studying bones is like reading the personal diaries of the dead.
I'm always a little bit in awe when I do get to handle human remains, because it's one of the last stories that these people can tell-- what they experienced in life.
"I died young, I had this infection," or, "I died peacefully.
" NARRATOR: Jacqueline determines that a minimum of 105 individuals were buried in the Samdzong cave tombs.
Later, carbon dating of the remains will show the people lived between 400 and 650 AD.
But there's something unusual about how the ancient people treated their dead.
Here's a couple of ALDENDERFER: Good God! That's a cut mark.
NARRATOR: Clear cut marks from a knife are evident on many of the bones.
In some instances, multiple cuts are found in one place.
This is not the distinctive pattern of cannibalism, but it indicates the Samdzong people were dismembering and defleshing their dead.
This bears some resemblance to the local funeral practices today-- the Buddhist ritual of sky burial.
When a villager dies here, they're not buried underground, but are offered in a high place to birds of prey to ensure the deceased do not return to their bodies.
CHARLES RAMBLE: At the present time, as soon as somebody dies, the first thing that the family will do is to break that person's back, because they have a visceral fear of the dead body becoming a rolang which is a term generally translated as "zombie.
" The idea is that a person dies, and his or her consciousness departs from the body, doesn't realize it's dead, sees the body there, and then tries to reinhabit it.
This is one of the reasons, they say, why they don't bury the dead, because they might rise again.
(man praying) NARRATOR: The flesh and even the bones are cut into small enough pieces for the vultures to consume.
But unlike the ancient bones preserved in the caves, this Buddhist sky burial is performed to ensure nothing of the body remains.
Its purpose is to give the dead a chance of being reincarnated, to live another life.
NARRATOR: Buddhism, with its custom of sky burials, is thought to have spread through this part of the Himalayas more than a century after the Samdzong people lived and died here.
ALDENDERFER: All right.
NARRATOR: Yet, an artifact found in one of the Samdzong tombs challenges this notion.
There are some interesting Buddhist-era remains in that that we did not expect whatsoever.
It's like a little plaque made out of clay.
And it's got a seated Buddha.
NARRATOR: A Buddha in a cave with human bones seems out of place.
ALDENDERFER: It's a very funny mixture.
they're still doing the defleshing, but yet they've got Buddhist elements with them.
Yeah.
Go figure.
NARRATOR: Why does a cave holding the defleshed bones of a people predating Buddhism by more than a century have an image of the Buddha in it? Early Buddhism and how it spread is really a big open question.
Nobody's really found clear and convincing evidence of their mortuary patterns.
So these findings are pretty exciting.
NARRATOR: This could be the earliest Buddhist relic ever found in the high Himalaya.
Look how fragile.
RAMBLE: You have this Buddhist artifact there, which seems to be much earlier than it ould be.
In theory it should be no older than the 7th century, but the archaeological evidence seems to suggest it is older.
So we have Buddhism on the edges of the Tibetan Plateau at least quite a long time before the official introduction of the religion into the area.
What you also have is evidence of a type of burial that precedes the Buddhist form of burial that took over in Tibet in the late 8th century.
So the fact that Buddhism is also present does indicate that we're at a transitional stage.
NARRATOR: It's possible Buddhism started earlier here than previously known, and people buried the bones of the dead after removing the flesh.
The rite perhaps foreshadowed the sky burial practice of today.
A forensic investigation of Samdzong's artifacts commences, to determine their possible origins.
One cave had a coffin-like bed inside.
Hmm, that's leather.
WOMAN: That's leather.
NARRATOR: Alongside the bed were the remains of a horse and some horsetack, suggesting the body was that of a prominent individual.
Rich artifacts like a large copper pot, bronze bracelets, iron daggers, and glass beads littered the grave.
Two mysterious pieces of metal were also found in the cave.
SUSAN: Wow! I really don't want to flatten it too much.
So, that look like a nose? CLEO: That kind of looks like an eye.
ALDENFERDER: We have two masks.
NARRATOR: They are death masks, and there's even a third one.
CLEO (whispering): Please don't break! ALDENFERDER: Here we go.
Check it out.
This guy's got more color.
NARRATOR: They need to determine what metals the masks are composed of and where they were made.
So a sample is sent to University College London for analysis by metallurgist Giovanni Massa.
He found there are two layers of precious metals in the masks.
GIOVANNI MASSA: What you see in this picture is a section of one of the masks.
and you can clearly see there are two different colors-- the front, in yellow color, which is the gold layer, and the silver, which is the back of the mask.
The technique that they used was hammer welding.
NARRATOR: There are no gold and silver deposits to be found nearby, and the technology needed to hammer gold and silver into death masks indicates the craftsperson who created them was highly skilled.
MASSA: What is actually very striking is the thinness of the mask-- around 50 microns, which is less than the thickness of a human hair.
In fact, to make the artifact, you won't need a lot of material.
You would need a sphere of about this size for the silver layer and an even less amount of gold.
NARRATOR: Pinholes can be detected on the outer rim of the mask.
MASSA: The pinholes were used to attach the mask to something else in order to actually have it stable on the face of the person.
I think the mask was actually sewn onto a fabric and the glass beads were sewn onto that fabric as well, and formed fairly elaborate headdress.
The mask covered the face, the fabric covered the head, and then the glass beads were covering that fabric itself, draped down over the shoulders onto the chest.
Must've been absolutely spectacular.
MASSA: What you see is an incredibly rich collection of artifacts.
Pretty much any alloy you could think of.
One of the medallions found is stylistically completely different from the rest of the collection.
You have the copper vessels that are just hammered surfaces, very simple.
You have the brass bangles that have very simple decorations.
And then you have this beautiful medallion.
All this shows that these people were connected to a network.
NARRATOR: By the time the Samdzong people were adorning their dead with gold masks, traders from Asia were exchanging goods with Europeans along an ancient trade route to the north called the Silk Road.
The cave-buried people might have come from the vast area we know today as China.
Or are these simply trade goods from the north? They need more evidence.
A single piece of cloth found in one of the caves could provide a clue.
Textile expert Margarita Gleba at University College London made a discovery using a scanning electron microscope that can magnify specimens up to 30,000 times.
MARGARITA GLEBA: This textile seemed to be made in what we call plain weave, or also known as tabby.
Tabby.
And that is the simplest type of weave you can create on a loom.
So it's one over, one under.
A curious thing with this particular sample is that all the fibers appear to be parallel to each other, but they're not twisted in any way.
NARRATOR: Most thread or yarn is produced by spinning short fibers, like this wool.
The twisting action gathers them together into a single long thread.
The only fiber that allows you to produce a thread without a specific twist is silk.
And the reason for that is that silk fibers are extremely long.
A single silk fiber, when unrolled directly from a silk cocoon, can reach up to two kilometers in length.
We can be quite sure that we are dealing with Chinese silk.
NARRATOR: Since the cloth found in the cave is silk, could this suggest the people came from China? The Samdzong remains only date to 400 AD.
The earliest known pottery in the region dates back to 800 BC, so there must have been people earlier than Samdzong.
And Mark wants to find them.
Today's archaeological objective is a cave at 10,000 feet known as Rhi Rhi.
It's a few hours' journey from the nearest town.
A complete kitchen, cook staff, climbing gear, tents, and food make up the loads which will have to be carried across a river called the Kali Ghandaki.
This is the deepest river gorge in the world, carved by the glacial meltwaters of some of the world's highest mountains.
Any other time of the year, the river runs so high here it's impassable.
With anchors firmly in place, Pete can rappel down a slope most climbers would avoid altogether.
Pete leads another double rappel with Mark.
ALDENDERFER: Hold on a sec.
ATHANS: Okay, you can just keep lowering yourself in till you're seated at the edge.
There you go.
We're good.
NARRATOR: It doesn't take long for them to find what they're looking for.
ALDENDERFER: These are all human bones that we're coming up with at the moment.
NARRATOR: A hand-carved wooden peg is among the first artifacts found.
It looks like one of those little daggers.
That's a really cool thing.
NARRATOR: What Mark really wants to find is black pottery that would suggest the burials are around 3,000 years old.
This is some good pottery.
Oh, look, yeah, there's blackware, too, wow.
Very nice.
Thank you, Satish.
NARRATOR: The pots are definitely black, with characteristic thick handles.
Carbon dating later confirms the burials are 2,800 years old, among the earliest ever found in the Himalayas.
Mark unearths a deep hole in the cave, where the early people were entombed.
ALDENDERFER: What we're looking at is a pit.
And then at some time they just bring them up here, open up the pit, and put them in, and then go back.
NARRATOR: They ultimately find the bones of about five people.
Am I good? Yep, you're good.
Okay, nice and easy.
Okay, I'm with you.
NARRATOR: For the local people, finding human bones can be unsettling, because they believe in completely eliminating the remains of a corpse after death.
Molecular anthropologist Christina Warinner notices that the bones have been disturbed and altered by visitors to the cave.
A group went in much, much later, and they applied ochre to the remains.
Ochre is this mineral pigment that's naturally occurring.
This red ochre has been rubbed on some of the bones, and in other cases sprinkled on them.
We know that it was applied after death, because we find it both on the exterior of the skeletal remains and also on interior surfaces.
So it must've been applied after the body had already decomposed.
NARRATOR: It's possible this was done by Buddhists, long after the initial burials.
So they didn't just ignore them or remove them, but actually actively engaged with them.
That's very unusual for this region.
NARRATOR: Another find from the cave supports this theory.
Mixed in with the bones, and broken into pieces, was a one-foot-square ceramic object, marked with strange engravings.
ALDENDERFER: If you look carefully at the surface, you see little daggers.
The use of these daggers like this is usually some kind of exorcism that's taking place to get rid of some sort of evil or maleficent spirit that happens to inhabit a place.
RAMBLE: "Dagger" describes the object that's called in Tibetan phurba.
A stake, basically.
And it's like any spike, the fundamental purpose is to hold something down, to stab it ritually and make sure it stays down.
NARRATOR: Mark believes the dagger object was left by later visitors to the cave, probably early Buddhists performing an exorcism in reaction to finding the bones.
ALDENDERFER: They enter these sites at some time in the past after the people have been buried in them.
They encounter the bones, and then they become frightened by them.
NARRATOR: If this interpretation is right, the daggers symbolically hold down the bones, like stakes, to prevent them from becoming reanimated.
The remains of the original occupants of the cave are from some of the earliest people yet found.
Mark wants to figure out where they came from.
For years, scientists believed these people migrated from the south, what is now India, because it was much more populated than the Tibetan Plateau and the lands to the north, now China.
A discovery in the early 1990s seemed to confirm the link to India.
In a cave complex in Mustang called Mebrak, German and Nepali archaeologists discovered the Himalaya's first mummies, naturally preserved by cold and dry conditions.
Carbon dating placed the 42 individuals as far back as 400 BC.
Since their discovery, the mummies have been stored in Kathmandu, until Mark received permission to examine the remains.
There's still a little bit of flesh on it.
You got that right.
NARRATOR: Some are still intact, like this mummified two-month-old baby.
Some of the bodies were found on wooden bunk-like beds, in a fetal position, ankles and wrists bound together with cloth.
No other burials like this have ever been seen in the Himalayas.
The artifacts look like they originate from the south, from what is now India, and include ornamental gourds, carved wood, a bamboo flute, and even glass beads.
India has been making glass for over 3,000 years.
This suggests the early people of the Himalaya could've come from India.
But it's not that simple.
Each cave burial the team uncovers in Mustang is different from the others.
Some are defleshed, some buried in pits, and others found on bunk beds.
There are influences from a number of regions, so the settlers could have been from different cultures across Asia.
There's a mystery here that can't be solved by examining artifacts alone.
CHRISTINA WARINNER: Many people proposed different hypotheses about where the people initially came from who colonized the Himalayan mountains.
But none of these lines of evidence was conclusive.
What we really needed was DNA from those first people in order to solve that problem.
NARRATOR: DNA is the double helix strands of chemicals in our cells that carry our genetic information and can reveal what we've inherited from our ancestors.
If Mark can procure DNA from the cave burials, he can find clues to their origins.
Upper molar two.
NARRATOR: A tooth's enamel is the hardest tissue we have.
It can protect the DNA preserved within the tooth for thousands of years.
Mark extracts teeth from the Mebrak mummies to add to his samples from the other caves.
ALDENDERFER: This one was very hard because it has much flesh keeping it together.
NARRATOR: For the teeth that are difficult to extract, he plays dentist to the dead and uses a rotary tool to free the tooth from the 2,300 year-old mandible.
The teeth go to Christina Warinner's lab at the University of Oklahoma.
It's a highly sterile workplace, built to protect ancient samples from the modern DNA that surrounds us.
WARINNER: There is DNA everywhere.
Every time you cough or sneeze, you're putting DNA into the air.
So if we want to be able to recover this very ancient and degraded material, we have to get rid of all of that extraneous DNA as much as possible.
So we conduct this work in special laboratories that have highly filtered air.
We have ultraviolet radiation built into the ceiling to sterilize the room in between uses, and we wear these Tyvek suits, which help keep our DNA in.
Most people, when they see them, they're used to seeing them in context of people in epidemics trying to protect themselves from disease.
We wear them for the reverse reason.
We're trying to protect our samples from our DNA.
We clean the teeth with bleach to remove and destroy any DNA on the surface.
In a way, it's almost like getting a very belated dental cleaning.
We use an abrasive tool to remove the outer layer, to really scrape off these contaminants.
And then we use ultraviolet radiation that causes damage in any DNA that's still remaining on the surface.
We can then liberate the DNA from the tooth itself.
NARRATOR: Tina's meticulous cleaning methods pay off.
She's found some of the best-preserved ancient DNA ever sequenced.
WARINNER: That is extraordinary, and likely resulted because the region is so cold and dry.
NARRATOR: 100 milligrams of tooth material, about the size of a pea, is all that's needed to fully sequence a single human genome-- the genetic blueprint unique to each of us that contains traces of our ancestors' DNA.
WARINNER: We can take these pieces of DNA.
From that, we can painstakingly reconstruct the genome of that person, and learn all sorts of things about them-- what they looked like, if they're male or female.
We can learn where their ancestors came from.
NARRATOR: Geneticists can find out clues to our origins by looking closely at small variations in our DNA and comparing them to other groups.
Population geneticist Anna Di Rienzo found that the genomes of all the samples collected in Mustang, even those from different caves, are very similar.
ANNA DI RIENZO: One of the major findings of our study is that the gene pool of these populations hasn't changed in a major way over the period of time that we have sampled, which is roughly 3,000 years.
NARRATOR: After comparing the samples from the cave people with each other, Anna then compared the genomes with different present-day populations around the world.
She's looking at small sections of their DNA for similarities and differences in the order of DNA's four chemical bases, abbreviated as A, C, T, and G.
We can ask with this analysis, "Who are the populations that are closest genetically to our samples?" NARRATOR: Surprisingly, there was no match with people from any part of India today.
The results indicated the Himalayan peoples are most closely related to East Asians, including today's Japanese, Han Chinese, Tibetans, and the Sherpas, who live near Mount Everest.
So the earliest Himalayan people came from the north, from East Asia and the Tibetan Plateau.
Although their burial customs differed from one group to another, and some had artifacts from India, and lived at different times, genetically, all the cave people were very close.
WARINNER: The genetics were incredibly stable through time.
This was fascinating to us because we saw big changes.
For example, between the Mebrak and the Samdzong period, we suddenly see defleshing.
That's a new thing, that's a religious change, and yet we don't see any change in the underlying genetics of the population.
NARRATOR: But researchers have spotted one genetic change specific to high-altitude peoples of the Himalaya.
It's an ancient mutation, or gene variation, a change in the order of the chemical bases-- the As, Ts, Cs and Gs that make up the gene.
The variant prevents people from getting sick at high altitude where the available oxygen is low.
WARINNER: There are a few places in the genome, a few traits in which we have experienced very recent evolution.
So one of these would be the adaptation to high altitude.
There's only a handful of these genes that are very, very recently undergoing selection, and this is one of them.
NARRATOR: Most of the Himalayan people that live here now have this variant.
The team wants to know if the ancient people buried in the caves also had this mutated version of the gene.
To gather even more DNA samples, the team heads to another burial site, in a region called Nar-Phu, where there are reportedly hundreds of bones.
Although it's only 30 miles away as the crow flies due east, getting there takes three days of driving and another three days on foot.
It'll take ten hours to hike to 12,000 feet in a day, a rapid 4,000-foot gain in elevation-- not enough time for most people to acclimatize, or adjust, to the altitude.
ATHANS: Now, you'll see as we're walking uphill, steadily gaining elevation, we have to breathe a lot heavier.
Might just feel like our performance is really down.
Now, a lot of the locals don't really feel that, because they have that special makeup in their DNA, and it allows them to acclimatize very quickly.
Meanwhile we're out of breath.
We're definitely feeling a lack of performance.
We might feel like we have a little bit of a headache, a little dizziness.
NARRATOR: There's about 35% less oxygen available here than at sea level, so the team keeps track of how much oxygen is getting into their bloodstream as their bodies adapt.
We're at Meta, which is at about 11,700 feet, and we're just going to be checking the level of oxygen concentration in the bloodstream with a pulse oximeter.
The lower number is the pulse rate, and the upper number is the percentage of oxygen that's being carried by the blood.
NARRATOR: When we breathe, oxygen enters our bloodstream and provides our cells the fuel they need to carry out their jobs.
At sea level, a healthy person should have at least 95% oxygen saturating their blood cells.
But at 12,000 feet, lowlanders who first arrive will only have between 80 and 90%.
ATHANS: There is about an 82% carrying capacity of O2, percentage of oxygen in the bloodstream currently.
And their pulse is at about 108, 109.
These are fairly common numbers, actually, for arrival at altitude.
For unacclimatized folks.
For an unacclimatized person.
Yeah.
NARRATOR: If Mark were at sea level, 82% would be a low blood oxygen saturation, called hypoxia, and he'd be given bottled oxygen to breathe.
But at altitude, this figure is normal.
In contrast, Himalayan people can tolerate low levels of oxygen, thanks to a genetic trait.
ALDENDERFER: Somebody who lives at altitude that's got the appropriate genetic adaptations, I'd expect their pulse rate to be lower.
I'd also expect their oxygen saturation to be significantly higher than folks like me.
I guess we'll test that now.
Temba, where were you born? I was born in the Everest region, which is elevation about 12,600 feet.
My expectation is that Temba will have a relatively low pulse rate, and he'll also have a relatively high oxygen saturation in his blood, because he's adapted to high elevation life genetically.
Your saturation is what? I can't see it very well.
92, 91.
And his pulse rate is 78.
You know, pretty typical for folks that are adapted to this kind of life.
NARRATOR: If most of the people living here today have this genetic variant, the question is, when and where did this adaptation begin to appear? The team moves ever higher into the cold and arid alpine zone at 13,000 feet.
It's a wonder people came to settle here at all.
The villages are abandoned as locals have gone to higher pastures for foraging.
Life is hard here, which is why the Himalayas were settled so late.
ALDENDERFER: If you look at the pattern of human migration over the last two million years, mountains are one of the last places on the planet to in fact be occupied.
Deserts come earlier.
Polar extremes, like around the Arctic Circle, come somewhat earlier as well.
Mountains come somewhat later.
These are difficult places for people to live.
NARRATOR: They've reached their destination of Kyang.
The village feels like a ghost town.
There's really nobody around.
I walked through just trying to talk with some people, but it didn't look like I mean, there were a few donkey people just around the corner, but they left about 15, 20 minutes ago.
NARRATOR: These are the same pastures the early inhabitants used for their animals thousands of years ago.
ALDENDERFER: Somebody lived here some long time ago, built the site, and buried their dead somewhere around here on these relatively fertile pieces of ground surrounded by these incredible vertical environments.
We will have to find out what the dates are, and if there's any associated artifacts that give us a sense of what this group of people might be related to.
Because right now they're essentially unknown to us, except for the fact that they exist.
NARRATOR: The team is anxious to see if Pete can get inside the cave.
FINN CLARK: We can watch with the GoPro what Dad's doing, filming, on here live.
NARRATOR: About 800 vertical feet above the village is the naturally occurring cave with manmade walls stacked above it.
Work our way up, like from the right, up and around the cleft.
NARRATOR: Pete's objective is to get safely inside to photograph the interior.
ATHANS: We're at the base of the big crack now.
It's just that it's exposed, and there's a lot of loose rock stacked up on the ledges.
If you grab the wrong handhold or foothold you could send a big rock down or you could fall.
NARRATOR: Pete free-climbs the large crack leading deep into the cave.
He'll place an anchor above him for a safety rope if he falls.
ATHANS: Going up into the cleft and way back into the dark wearing a respirator mask and a headlamp, it can be very narrow.
I can certainly get very claustrophobic moving in there.
It's very dusty inside.
There's a lot of remains from birds and bats and every manner of rodent in there.
You're just inching your way up through this crevice, and then you enter this very spacious bone room.
It was very much crypt-like.
ATHANS (on walkie-talkie): Hey Mark, you guys copy? Yes, we copy, Pete.
I have a couple of jaws here, couple ephemera, and then a few other human pieces.
A piece of wood that's pretty interesting that are all in a bag right here we'll collect on the way down, break.
NARRATOR: The climb is too technical for the scientists to get inside.
So, Pete maps out sections of the cave on a grid, and all bones and artifacts are bagged according to their location.
ATHANS: The process with the grid that we're lining out is really just to try to give the archaeologists an idea of where in the cave these materials were actually taken from.
NARRATOR: The original burials have been disturbed, most likely by looters looking for valuable funerary goods.
ATHANS: There's a real scattering of materials.
It looks like someone had actually been doing some digging right down in this area to my left.
So we're looking at a context that's more disturbed than I had anticipated.
NARRATOR: It takes three days to fully excavate every bone and artifact from the cave.
ALDENDERFER: Okay, I've got the bag, if you guys pull.
NARRATOR: The next step is to look for signs of death rituals.
People's heads.
People's heads, yes.
NARRATOR: The presence of animal bones suggests they were sacrificed to bury with their human owners.
ALDENDERFER: This is a very common pattern in this part of the world, is to inter the dead with domesticated animals of one kind or another.
Here in Kyang the only ones that we've seen so far are sheep or goat.
RAMBLE: If you find animals in a grave like that, there's got to be a reason for it.
It's most likely that the animals were sacrificed and placed with the dead person for one of two reasons-- either to be food in the next life, to constitute part of his or her herd, or as the animal that guided the dead in the afterworld.
(collar bells ringing) NARRATOR: Every scrap of evidence is analyzed.
ALDENDERFER: It's definitely been imprinted on there somehow.
Good eye, Finn.
I bet if we wet it in water Oh yeah, check it out.
There it is.
Can you see it more clearly? Very nice artefact.
NARRATOR: It's a simple bamboo stick, but the woven pattern on it suggests it was once part of a basket.
Later, carbon dating reveals the people of Kyang lived around 200 BC-- the same time as the Mebrak mummies.
Their artifacts appear to be locally made, indicating the people were self sufficient and lived off the land.
The bamboo and wood could've come from nearby.
This is a very nice wooden bowl.
Soft wood.
It has a really lovely little base on it that's been made, and it imitates a bowl that's been made on a wheel.
So it's been carved to look like that.
NARRATOR: Jacqueline determines 23 people were buried in the Kyang cave, with no cut marks, and the presence of flesh on the joints suggests they were buried whole.
But the ages of the dead are surprising.
ENG: Several of these individuals were younger than 20.
Several of the adult remains are also younger adults, so below the age of 30, 35, and that suggests that people did die of something that shortened their lives.
Could be starvation, could be an infectious disease that, you know, moved really rapidly.
NARRATOR: An enigmatic object found in the cave hints at ritual practices that may be connected to these premature deaths.
One of the most interesting things we found during this work here at Kyang is this special stick.
You can see it's well-carved.
It's thin at the bottom, widens out.
Clearly it's been meant to either be put in the earth or maybe in a socket of some kind.
The first thing that jumps out when you look at this under the microscope that we have here in the field is those are little tiny pebbles that have been placed inside little tiny divots.
And the divots are holding glue, some kind of cement that hold these things in place.
But if you look at this image, it's the image of a person.
What I really think this person is doing is holding something we found in the archaeological site, what I've been calling fire sticks.
They're little sticks.
They might be four or five inches long, and usually one end is burned.
You can see the wavy or sinuous line, which I would interpret as smoke coming out of the end of that firestick.
NARRATOR: Cultural artifacts open a window on a people's long-vanished beliefs.
The humanoid figure on the stick is so unusual, Mark travels to France to see if anthropologist Charles Ramble can make sense of it.
Charles specializes in the ritual practices of Himalayan peoples.
What's the material? This is not just discoloration from water or something? ALDENDERFER: No, not at all.
That's actually what they've done to highlight, they've ground up some dark stone into very fine particles, and then literally pushed it into the outline of this to kind of emphasize and bring out the contrast.
So all this was intended.
All this was very much intended.
RAMBLE: (reading Tibetan text) NARRATOR: Charles has recently discovered an ancient text that describes a death ritual using sticks called firebrands, much like the ones Mark found.
RAMBLE: Tibetans believed that people died because their souls were taken away by death demons.
And these are known variously as shi or as shay.
Shi is commonly translated as "vampire.
" And rituals had to be performed afterwards in order to separate the soul from the demons who had taken it.
"I am Taklamembar, and this is how "the vampire-killing firebrand, the emanation of my mind, "came into being.
"The demon of bad death among males was killed "with the firebrands.
"The demoness of bad death among women was killed with the firebrands.
" There is one text-- its title translates as "The Origin Tale of the Firebrands for Killing Vampires.
" These firebrands in this text are being used as a means of killing vampires, and vampires are the agents that are responsible for death.
They are serial killers.
So if people of a certain age between 20 and 30 die in a series, that's the effect of vampires.
So the vampires are something that steal vitality, and eventually life.
And they latch themselves onto a family, and they will continue to affect that family until they are got rid of.
NARRATOR: This may explain why the firestick was found in the Kyang cave with young adults who died prematurely.
RAMBLE: It's unusual that we can find textual evidence to support archaeological evidence.
"The killing of vampires with the firebrand is over.
"May there be good fortune, good luck, blessings, and virtue.
" Stakes of this sort are very ancient.
They've been found in many parts of central Tibet, and also at the foot of the Great Wall.
And they date back to the third century BC.
NARRATOR: The discovery of stick effigies at the foot of China's Great Wall is another piece of evidence confirming these people could've come from there.
With DNA recovered from each cave population, the scientists can see, over a 3,000-year timespan, which of them was adapted to survive at altitude, and when the adaptation appeared.
DI RIENZO: An important feature of the study is that it provides ancient DNA samples and data from different time points in the past.
We can see how the data changes over time.
And this is what we call watching evolution in action.
NARRATOR: Anna finds that all of the people buried in the caves have the high altitude adaptation.
But the study of their DNA reveals there's a second adaptation that also enables people to live at altitude.
The earliest of the cave people have the first genetic variant, but the most recent burials, the Samdzong people, acquired a second variant.
Both variants are seen in the people of the region today.
The most surprising aspect of this variant is that scientists have seen it before.
In 2008, the tiny pinky bone of an extinct human ancestor was discovered in a cave in the Altai mountains of Siberia, called Denisova.
The 41,000-year-old pinky bone had just enough DNA in it to be sequenced.
The individual was female, young, and had that second adaptation.
DI RIENZO: This Denisovan population that had a relatively wide geographic distribution in Asia, maybe they already had adapted to high altitude.
That's part of the history that we would like to dissect.
NARRATOR: At some point in prehistory, Homo sapiens, our modern human species, must have mated with the now-extinct Denisovans.
It's likely the only way humans could have obtained the second high altitude gene adaptation.
We don't know exactly where the encounter between this Denisovan-like population and the modern human populations occurred.
It's possible that this mutation was present in the Denisovan-like population but was not advantageous, yet after the mixing between these two, and the modern human population moved to high altitude, it became advantageous.
NARRATOR: This important DNA variant, or allele, from an extinct human ancestor, is part of the genetic inheritance of Himalayan people today.
DI RIENZO: The finding was very exciting.
It's telling us something more than just the fact that modern humans and Denisovans mixed, but also that Denisovans gave modern humans an allele that allowed them to conquer this so-called Third Pole, and to adapt to these very harsh conditions of high altitude hypoxia.
NARRATOR: Genetics and the study of ancient DNA allow us to see modern human evolution in action.
WARINNER: This new ability that we have to actually sequence ancient genomes is teaching us so much we didn't know about human history and prehistory.
So, already, we're rewriting the storybook of humanity.
ENG: We're definitely still evolving.
The point at which we stop evolving is when we're an extinct species.
That's the end of evolution right there.
Those slight changes give us the ability to adapt to changing environmental conditions.
NARRATOR: Here in the Himalayas we can trace how we evolve over time.
That the people here can thrive at altitude shows just how adaptable we as a species can be.
We now know more about the early cave peoples' beliefs, and how they endured one of the toughest places on Earth.
And the knowledge gained by recovering ancient DNA and deciphering death rituals provides a clearer picture of the unique heritage of the mountain peoples who live at the roof of the world.
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