Ancient Impossible (2014) s01e10 Episode Script

Extreme Engineering

How did the ancients build a beacon taller than the tallest lighthouse in America today? Were the ancient Egyptians capable of creating a giant circular saw that could cut through solid granite? How did Julius Caesar build a bridge across the mighty rhine river in just ten days and then march his army of over 40,000 across it? And the secrets of the greatest harbor of the ancient world, Rome's Portus.
Monuments more colossal than our own, ancient super weapons as mighty as today's, technology so precise, it defies reinvention.
The ancient world was not primitive.
Their marvels are so advanced, we still use them now.
Travel to a world closer than we imagine, an ancient age where nothing was impossible.
In the modern world, iconic manmade structures reach out across the oceans, welcoming beacons of progress.
The statue of Liberty, 300 feet tall, dominates New York harbor.
But is it possible that this engineering marvel would have been dwarfed by a construction created by ancient engineers over 2,000 years ago? And what of this, the Cape Hatteras lighthouse in North Carolina? It's the tallest in the United States.
Could there have been an ancient lighthouse twice as high? The answer to both these questions lies in one incredible structure.
It's a building that's shrouded in legend and rumor, but not only did it exist, it stood for over 1,500 years.
It was the Pharos, the great lighthouse of Alexandria.
The lighthouse at Alexandria was the daddy of all lighthouses.
It was one of the tallest manmade structures on Earth for centuries and even compared to modern lighthouses, it stood head and shoulders above them.
This lighthouse is 85 feet tall.
That's pretty big.
The lighthouse at Alexandria around 400 feet high.
That's impossibly big.
The Pharos lighthouse was one of the seven wonders of the world and deserved to be.
It was one of the tallest and most massive buildings, and it was built to a very, very high standard indeed.
There'd never been anything like the Pharos lighthouse before.
The structure of the lighthouse at Alexandria was incredible.
It had a huge square base.
It was made of granite blocks that were sealed together with molten lead to protect it from the waves.
Next came an octagonal tier and on top of that, a cylindrical tier.
It would've dwarfed this.
It was the equivalent of a 40 story building.
Julius Caesar called it a work of wonderful construction.
Modern lighthouses like this one in happisburgh, England, are by comparison small, temporary structures.
This lighthouse has stood for around two centuries.
That's better than some.
But the Pharos lighthouse, it was built around 280 BC and was still standing in the 1,300s, over 1,500 years.
That's unbelievable.
It was the first, the biggest, and the best.
It set the benchmark, and when the Romans came across it, they saw how useful lighthouses could be and built them throughout their empire.
The remains of one can still be seen in Dover, England.
Dover was the key harbor into Britain.
The lighthouse here was incredibly important.
This one looks impressive the one in Alexandria absolutely blows it out of the water.
It's almost impossible to believe that they could martial that kind of architectural and engineering expertise.
But they did.
Did the lighthouse at Alexandria really need to be so tall? Well, it was built for the kings of Egypt, and they wanted to make a grand statement.
This was built by the dynasty of kings who succeeded Alexander the great in Egypt.
They regarded Alexandria as a great theater for projecting their power and magnificence and grandeur.
Everything had to be bigger and better than it was anywhere else.
Bit like New York, really.
It was so impressive that people from around the known world travelled to see this miracle wonder of a building.
They used to stamp pictures of it on coins.
They used to sell models of it, and when visitors arrived, they could buy their ticket.
It was basically the empire state building of its day.
It was that famous.
There's talk of an observation platform, and I wouldn't be at all surprised if there were people up there selling the ancient equivalent of hamburgers and little models of the lighthouse that they could take back to to their homes.
At Dover, the Romans were less interested in tourism.
They had an empire to build and wanted to make sure their ships had safe passage.
This lighthouse didn't stand alone.
It was actually part of a pair with another tower over there on the Western heights, and they stood either side of the natural harbor in Dover.
And with a similar setup across the channel in France, Roman sailors could safely navigate between the two.
By using the towers together, seamen could effectively use an ancient form of GPS To know exactly where they were and how to travel safely and find safe passage to the harbors.
It was pretty clever.
At night, the Roman lighthouses burnt dry wood to create the brightest fire.
In the daytime, they probably burnt wet wood, which would create a smoke signal.
The most incredible thing about the Pharos lighthouse is the accounts of something unbelievably high tech in use at the top with remarkable similarities to a modern lighthouse.
This is the important part of a lighthouse.
Originally, there would have been candle lanterns in here, but like all modern lighthouses we've got electricity and we've got prisms to focus the light.
This light from the lighthouse can be seen 18 miles out to sea.
The Pharos lighthouse could be seen 30 miles out to sea.
It makes you wonder what was generating that light.
During the day a distinct possibility would be the use of large mirrors, which might well have been rotated to give a flashing effect like the sort of thing you get in modern lighthouses.
A flashing lighthouse just like today's over 2,000 years ago.
This sounds impossible, but model maker Richard Windley has recreated how it might have worked.
My theory, and it is only a theory, is that a mirror would collect the sun's rays from somewhere in this direction into this top mirror which had to be precisely angled so that the beam went absolutely vertically down below.
The beam would be reflected down below to the mirror here, which then could be rotated to distribute the light, a bit in the same way as a modern lighthouse would do.
A great mystery has arisen behind the use of mirrors in the Pharos.
Could there have been more to them than just providing safe passage? We are told that the mirrors could be used to concentrate the rays of the sun to destroy ships.
An incredible ancient weapon, like something from the space age.
Could it have been true? Alexandria was home to the greatest library of the ancient world, and the city wanted it protected.
But even if there was no super weapon, just the rumor of one would have been enough to make anyone think twice before attacking Alexandria.
It wouldn't do any harm, would it, if the word got out that they had a kind of super ray gun on top of the Pharos lighthouse that could destroy ships, very much, "don't tread on me or else.
" The lighthouse was certainly in a good defensive position.
That's why today, this 15th century fortress marks the location.
With or without the ancient super weapon, the Pharos of Alexandria was one of the most extreme examples of ancient engineering.
The lighthouse at Alexandria was truly a wonder of the ancient world, the size of a modern skyscraper.
Even today, it would be thought of as an amazing feat.
It's never been bettered.
The Pharos was built so well that it took multiple Earthquakes to eventually bring it down in the 14th century.
It was a dramatic end to an incredible construction.
Many of the most incredible engineering projects of the ancient world happened in Egypt thousands of years ago.
They built amazing structures, incredible temples and tombs, the great sphinx, and the pyramids at giza.
But now there's evidence of more impossible engineering.
This mysterious stone slab was found at Abu Roash, site of the unfinished pyramid five miles from giza.
It was discovered near an ancient boat pit in which a boat would have been buried to transport a dead king to the afterlife.
Remarkably, the slab seems to suggest that the ancient Egyptians were using engineering techniques thought unknown until the 19th century, four and a half thousand years later, surely impossible.
The slab is made of granite, which is one of the hardest rocks.
We know that the Egyptians used copper tools, but copper is softer than granite.
And they managed to cut the granite so finely.
How did they do it? I find this line really intriguing.
I mean, if traditional theories are correct for how they would have polished this surface, there's no real reason that there should be this line.
That line really to me looks like a cut mark.
Let me show you something else which is really interesting.
If you put a horizontal right across the block, what you can see is that it's a very concave surface.
It's quite nice and uniform, but you can see it bows significantly in the middle.
The smoothness of the cut can only have been made by sawing rather than hacking.
The curvature of the rock suggests a particular type of saw, an impossibly modern saw.
The most controversial theory for how this granite slab could have been formed this way, to have a concave surface, is by cutting it with a giant circular saw.
It seems amazing of course because no circular saws have ever been found in ancient Egypt.
This would be astonishing.
According to the history books, the circular saw was invented at the end of the 18th century.
If these curves can be reproduced, perhaps it would be possible to deduce how they were made.
At this stone cutting factory near yeovil, England, they've been trying to find the answer.
They have to have been using a technology that is more advanced than we've given credit for, and I'd love to find out what that is.
Producing the curved profile is achieved with a modern circular saw by moving the saw across the stone.
Could an ancient circular saw have cut like this? But with the saw vertical to the rock, a straight lip is made at the end.
The Abu Roash slab has a curved lip, as if the saw came in horizontally.
You can see here that if we do a cut straight on to the surface, you will actually get a surface curve like that, that you see at Abu Roash.
But the Abu Roash slab has this most unusual thing inasmuch as a compound curve, and that can only be done by bringing the blade in at 45 degrees to the surface and drawing the slab along.
That reproduces exactly the pattern that we see on the slab.
At an angle of 45 degrees, a circular saw gives a curved profile to match the curvature of the saw.
It also leaves a curved lip whether it's the blade moving over the block or, more likely, the block being moved against the blade.
If you have the saw in a vertical plane, you are effectively moving the block like that.
That's a perfectly easy motion to do if you have some rollers and some people to move it.
But the ancient Egyptians didn't have electrically powered machinery like this.
And granite has to be cut with either high tensile steel or diamond blades.
The Egyptians didn't have steel, and cutting rock with diamond tipped saws is impossibly advanced engineering.
In fact, there's no evidence that the Egyptians had even discovered diamonds.
If the ancient Egyptians had engineering like this, history would have to be rewritten.
The intriguing thing now is if you look at those two curvatures, one in the flat plane and one in the vertical plane, and you extrapolate those circles back, you come back to a saw that's about 30 foot in diameter.
And that's very big.
A 30 foot circular saw.
It would have to have been vertical for slabs of stone to be easily fed in.
In fact, it would have to have been in some kind of specially made hole.
So you're looking for a pit in the ground about 10 or 12 feet deep.
Lo and behold, next door to the slab, there is a slot in the ground which exactly matches the dimensions of a saw that would have to be used for that slab here.
So I'm saying here, here's a slot alongside a pyramid that is not a boat pit.
These slots have been mislabeled as boat pits.
Could some of these pits really have contained giant circular saws? This would be incredible.
And what about the diamond? No trace of diamond has been found in any excavations.
They weren't looking for particles of diamond.
So I'm saying that next time a boat pit is excavated, a new one they've found, I suggest they look very carefully at the ends and do a very careful analysis of the sand they find there.
If they find the sand contains diamond, there's your smoking gun.
That's the thing that will prove they were saw pits, not boat pits.
But one piece of evidence has been found, and it's rock solid.
The strongest explanation for the Abu Roash slab could be a giant circular saw strong enough to cut through granite four and a half thousand years ago.
The extreme engineering of the ancient world made mega builds that still amaze us today.
2,000 years ago, Julius Caesar, one of Rome's greatest commanders, faced an impossible challenge A quarter of a mile wide and 30 feet deep the river rhine.
From the far bank, raiding German tribesmen threatened Caesar's new conquests.
On this side, the germanic tribes were quite happy.
They believed that any advance across the river was impossible.
But the Germans underestimated the engineering power of the Roman army and the all consuming ambition of Caesar.
To understand how the Roman army could bridge a river 2,000 years ago, we're looking at how the British army does it now.
Modern armies have access to high tech bridging equipment.
So to cross this river today, we've called in some help from the royal engineers.
These three high mobility trucks can deliver an instant bridge anywhere and at any time.
This is "able," automated bridge laying equipment.
Ten men can lay this 100 foot bridge in less than half an hour.
But Caesar's bridge would need impossible vital statistics as long as four football fields and supporting the weight of 40,000 troops.
How did the Roman army achieve this impossible task thousands of years before modern mobile bridging equipment? There's a fascinating clue here in ehrenbreitstein fortress, high above the river rhine.
These very substantial pieces of oak were recovered from the bed of the river rhine not far from here.
They've been carbon dated back to 50 years BC There's only one explanation for that these were part of Julius Caesar's bridge.
These piles driven into the riverbed reveal the type of bridge Caesar built.
They've been shaped by Roman engineers so they could be driven into the riverbed.
But when they were driving into the bed they weren't quite sure what they were going to come across.
They put pile shoes on the bottom so it could be driven in without splitting the wood.
And it seems almost unbelievable, but this nail was driven in by a Roman engineer.
But these piles were one and a half feet thick, 60 feet long and weighed over 2 tons.
How did they get them in? Today we use pile rigs like this.
It uses a 5 ton hammer and can drive 60 piles a day it's quite amazing that Caesar 2,000 years ago was doing exactly the same type of thing in order to get over the river rhine.
Just think about the size of this engineering challenge.
You've got to drive supports into the bottom of the river.
You've got to put beams across.
And then you've got to build a road on top of it.
But the supports were massive.
You couldn't just knock them in using a big hammer.
It seems impossible to believe, but Roman soldiers built their own pile drivers.
A system like this, it uses gravity.
At the top, we've got a great big granite block that gets pulled up on a block and tackle.
Let it go ba dunk! Thumps and drives it into the ground.
They had their tools.
They had trees.
They made this.
It's beautiful.
And these amazing pile drivers could float.
When we look at modern military engineers constructing a bridge, the principles haven't changed in 2,000 years the lessons come all the way back from Caesar's time.
As this rolled out in sections and another section was dropped in, that's exactly what Caesar's army did.
This amazing bridge created from the forest advanced across the river rhine impossibly fast.
It took just ten days.
Ten days that must have been absolutely astonishing to the Germans across the river.
A bridge that, in effect, secures the borders of Rome.
To defeat the strong currents of the rhine, Roman engineers created design features we can still see today in modern beam bridges.
You may think initially that what you should do is put them in vertically.
The Romans had a cracking idea.
You put them in at an angle.
That's upstream, so the force of the water is pushing them even more into the bed of the river, making it stronger.
For the terrified Germans, Caesar's bridge was an unimaginable display of extreme engineering.
But that didn't stop them from attacking it.
The germanic tribes realized they could float logs down the river to try and take out the bridge that was being built.
And to get over that, what the Romans did was put piles in upstream just to deflect and slow down any logs that were sent down to try and wipe out the bridge.
With the bridge complete, Caesar led his troops to face a German army that outnumbered him 10 to 1.
But the awestruck Germans fled.
Caesar's bridge enabled him to subdue the German tribes without having to fight them.
This intimidating feat of extreme engineering wasn't just a mighty bridge.
It was the ultimate strategic deterrent.
It was a phenomenal bridge.
Put that into context: During the second world war, a bridge was put across the Sangro river in Italy.
Slightly less, just over 1,100 feet, and it took them 9 days.
So in Roman times 1,300 feet, 10 days, second world war, 9 days.
This really was a massive statement by Caesar and his armies.
This was "we are Rome.
We can go where we wish.
Bow down before us.
" Today's deepwater ports are amazing feats of engineering built to accommodate huge container ships and millions of tons of cargo every year.
We're here in the port of San Diego.
Ports like this are really the lifeline of a nation.
Cargo from all over the world comes here.
This is one of the most important ports on the west coast of the United States.
But ports were even more important in the ancient world.
Whole empires depended on them, and none more so than Rome.
And the port of Rome, being the greatest of its kind, is simply known as Portus.
Portus was the major seaport that served the imperial city of ancient Rome.
It was about 20 miles outside the city, but it was linked to canals that took grain and other cargo directly into the heart of the city.
But there was one significant difference between Portus and many of our great modern harbors.
Portus was manmade.
San Diego is a natural harbor, one of the best harbors in the world.
Unlike San Diego, most of the areas around the mediterranean had no natural harbors.
Portus had to be built by hand to make it every bit as important as this harbor right here.
To build a harbor by hand is a mammoth engineering feat.
And for the Romans to achieve this 2,000 years ago on the scale of Portus is a seemingly impossible achievement.
The harbor infrastructure at Portus was incredibly sophisticated.
The main basin was almost 22 million square feet in surface area.
It had wharves and jetties, a shipbuilding area.
This was fantastic engineering.
The scale is simply astonishing, and to try to get a sense of it, at the University of Southampton in England, they're using the latest computer imaging techniques to re create the ancient port.
It's very much as if we're walking about the site of Portus, even though at the moment we're based here in the lab in southampton.
Data from geophysical surveys, laser imaging and photos taken from drones are all fed into computers.
This is cutting edge archaeology, and what they've unEarthed is awe inspiring.
We're talking about something at an incredible scale.
For the visiting provincial in their sea going ship, this was the first sight of Rome.
This was meant to really knock you for six and say, "oh, my god, I'm really arriving in the center of the world here.
" There was the massive imperial palace, at least three stories high.
And this ship repair building, impossibly big, nearly 800 feet long.
This is an absolutely enormous building, truly awe inspiring.
The logistics, the manpower, the scale of everything involved is quite overwhelming.
Portus wasn't the only artificial harbor in the ancient world.
Incredibly, in the 3rd century BC, a huge harbor was made at carthage on the north African coast, at that time, Rome's great rival.
It was big enough for over 200 ships to be built and serviced there.
The outer part was for merchant ships and then there was a hidden inner harbor for warships.
But typically, the Romans took things to another level.
Portus was over ten times bigger.
Why did the Romans go to such superhuman efforts? Why was such a huge port needed? In the 1st century, it's estimated that the population of Rome was about a million people, and that was too many mouths to feed from just the surrounding agricultural land.
So they needed to import grain into the city, and that's where Portus was key.
To prevent food riots, vast amounts of grain were imported from Egypt and from sicily.
If you keep the people fed, you keep them happy.
If they're starting to get hungry, if there isn't food available, if the shops are empty, there's trouble.
As the empire waned in the 6th century, so did the use of the port, and it began to silt up.
Eventually, buildings fell into disrepair.
But seeing the port come alive again gives us a sense of the reach and might of Roman power at its height.
The amazing thing about Portus is the scale of remains that we have to encounter there.
And, in turn, they give us a way into understanding the sheer scale of the Roman empire that it was at the heart of.
The greatest empire needed the greatest port.
And they wanted everyone else to see that they had it.
That's why they put so much effort and invested so much time and engineering skill into Portus.
They created one of the masterpieces of the ancient world.
Rome excelled in extreme engineering.
But hundreds of years before Roman records This tunnel was built without power tools Without tunneling machines Without dynamite.
And these ancient engineers surveyed so accurately that to this day, we don't know how they did it.
This is lake nemi, 19 miles south of Rome, Italy.
Every year, rainwater flooded the lake, making rich agricultural land unusable.
To solve the problem, ancient engineers achieved the impossible by tunneling right through a mountain.
There's a fantastic construction right over here.
Essentially, it is a tunnel used to drain away part of the water from the lake.
But you've got a mountain in between.
It's estimated that this tunnel was started over 2,500 years ago.
And to speed up construction, the builders dreamt up an impossible plan.
"Why not build a drainage tunnel right through the mountain? But not only that, let's start at both ends and see if we can meet in the middle.
" Now, that's a major challenge.
Modern engineers struggle with that, but the ancients did it.
3D analyst James Dean is using the latest technology to understand this feat of extreme engineering.
This incredible tunnel, built to drain and regulate the overflow, runs downhill from lake Nemi into this valley.
Two tunnels were dug, one from each side, with the aim of meeting in the middle.
The tunnels met just nine feet out vertically.
This tunnel was dug over two and a half thousand years ago.
As a feat of human endeavor, it's just incredible.
But it seems totally impossible they could survey it so accurately.
How did they do it? Modern tunnelers use lasers to dig a straight line.
It seems impossible that ancient engineers achieved this thousands of years ago it is wet.
It is damp.
It is freezing.
And then of course, I've got electric lights, but what do they have in antiquity? You had oil lamps, little niches that you would just carve into the side of the rock.
It's pretty pitiful.
And yet the engineers were astonishingly accurate.
Over a mile, this tunnel drops 41 feet, an average gradient of under one percent.
It's an extraordinary feat of ancient engineering.
Just two reference shafts were dug to make sure they dug in the right direction.
But how did they get the gradient right? They might have used this rudimentary Roman spirit level, a water trough with a mark at each end to show the correct incline.
The ancient tunnelers may have used this to harness gravity.
We don't even know if this instrument existed so early.
But we do know they somehow achieved the impossible.
Whatever methods the ancients used, the evidence that they achieved the impossible is here, 450 feet underground.
Ah, all right.
Now, you have Paulo up there, and I'm down here.
And what it represents is the two teams.
So up on top from lake nemi, we have the workmen cutting through and progressing about 3/4 of a mile.
But down below where I am, the other team was moving more slowly because this stone is so hard.
It's basalt stone.
So they only move 1/4 of a mile.
We still don't really know how they did it.
And the two tunnels met inside the mountain, and they were just a few feet out.
That's without any modern technology.
It's incredible.
And it was 400 to 500 years BC It appears impossible, but they did it.
Regulating the level of the lake didn't just protect farmland.
Several hundred years later, the Nemi tunnel enabled the emperor Caligula to build a vast floating palace and a temple to the goddess Diana.
And 2,000 years later, the tunnel enabled the lake to be drained to reveal caligula's ships.
It's incredible to think that you have this tunnel 2,500 years old or older draining out part of lake nemi with the same tunnel to reveal the great ships of caligula.
Without the nemi tunnel to take away millions of gallons of water, the two greatest ships to survive from the ancient world would never have been recovered.
And even today, the tunnel could protect the lake from flooding.
Today, every great city has a world beneath it tunnels, vaults, sewers, pipelines.
This is extreme modern engineering.
But could there have been underground engineering 1,500 years ago on the scale of a subterranean cathedral? Surely impossible.
In modern times, one of the most remarkable underground constructions was built in London, England, in the 19th century.
I'm here in finsbury park in north London.
I'm about to have a look at one of the subterranean wonders of this city.
Bradley Garrett is an expert in the hidden worlds beneath our cities.
These steps lead to an engineering marvel.
It's an empty victorian cistern, an underground reservoir that provided water for the city above.
Others are still in use beneath London and together they're quite rightly famed as a wonder of the victorian age.
This particular reservoir would have held something like five million gallons of water.
This is an incredible piece of architecture and not only a feat of engineering, but an aesthetically very beautiful space.
Incredible engineering like this kick started the modern world.
But on the other side of Europe, there's a modern city with an ancient past.
This is Istanbul, and beneath these streets is something extraordinary.
Perhaps our modern engineering isn't so modern after all.
I'm in the basilica cistern, which in turkish is known as "yerebatan sarayi," or "underground palace.
" And this is the largest water cistern in the city formally known as constantinople.
The basilica cistern is incredible.
It's massive, and it can hold up to 100,000 tons of water.
That's 22 million gallons of water.
The walls are 12 feet thick lined with waterproof cement.
It still works.
It still holds water.
Today, this would be an astonishing feat of engineering.
But incredibly, this cistern is Roman.
The groundbreaking, 6th century construction was overseen by the Roman emperor himself, justinian, successor to constantine and a man eager to make his mark it's said that the basilica cistern was built by 7,000 slaves, all under the command of emperor justinian himself.
This was engineering on a monumental scale.
To think that they undertook such a grand building project with what are basic and simple tools and methods is kind of beyond belief.
To a modern engineer, you'd think you just wouldn't be able to do it.
How did they build it? What was the engineering that was involved? Well, essentially, you had a massive labor force that dug out this space.
We're talking about men using pick axes and shovels and wicker baskets to haul away the dirt.
What's even more impressive of course is that that simple kind of technology, what they had available to them, still allowed them to build greatness.
This is like a cathedral.
The cistern could be a temple to Roman engineering.
In fact, many of these 336 marble columns came from disused temples across the empire.
The Romans are recycling a lot of marble for the cistern.
They also recycled this, a great discovery, and it is a medusa.
This is one that wards off evil in pagan times.
She's placed here and stacked with other blocks to get this smaller column up to the full height of the ceiling.
Is there some hidden meaning in the fact that this head is upside down? Well the thing is, this was in the cistern in the 6th century.
It was underwater.
Beyond that, we don't know.
But why have a water supply underground? Other cities were supplied with water from reservoirs, aqueducts, and canals.
The Romans were experts at this.
A few hundred years before, the Romans in the east had found out the hard way the value of cisterns in times of war.
For months, Jewish rebels on the hilltop fortress of Masada had held out against a massive Roman force, and they were able to do so because the underground cistern provided them with enough fresh water to endure the siege.
In Constantinople, the Romans were determined that they would have a secure supply of water in the heart of the city.
The city is impervious to attack, so if they're being besieged, they're going to have a massive water supply.
They've got that large supply.
They can withstand attack for a very long time.
It's a great engineering solution, and you wouldn't see a water supply on this scale for another 1,400 years.
Constantinople may have had the biggest, but it wasn't the only city in the ancient world with underground cisterns.
The people of Alexandria did exactly the same thing.
They built cisterns under their city.
It just goes to show how clever all these ancient civilizations were and how good they were at engineering solutions to the problems.
The basilica cistern remained unparalleled until well into modern times.
This is extreme engineering at its best.
It's astonishing to think that their work wasn't bettered for 1,500 years.
Ancient engineers set the standard for technology that forms a vital part of our modern world, from sophisticated navigation systems to precision cutting And ultra modern seaports, proving that the ancient world was able to achieve the impossible, creating extreme engineering that can still take your breath away.