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male narrator: An industrial
super factory
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thousands of years
ahead of its time...
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- This really was the world's
first mega factory.
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narrator: A huge
2,000-year-old building
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that grows stronger
the older it gets...
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- It's an enormous space.
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You could hold over
5,000 people.
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It's absolutely amazing.
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narrator:
A revolutionary machine
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that transformed cities...
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- If you can lift more,
you can build bigger.
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narrator:
And the most ambitious
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Roman engineering project
of them all.
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- Huge networks
transporting gallons
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upon gallons of water
across the empire.
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narrator:
Where will they be ranked
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in the only top ten list
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thousands of years
in the making?
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[dramatic music]
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♪ ♪
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Rome engineered an empire
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which stretched from
the Atlantic to the Tigress.
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At its peak,
there might have been
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up to 70 million citizens.
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The Romans shaped our world
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more than any other
civilization
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from antiquity.
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This week's "Ancient Top Ten,"
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Rome's Greatest Hits,
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amazing Roman feats
of engineering ranked
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by experts according to which
most changed the world.
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♪ ♪
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At number ten,
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courtesy of Julius Caesar,
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the bridge that beat
the barbarians.
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- Caesar's bridge
over the Rhine
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is incredible engineering
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amazingly executed.
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♪ ♪
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narrator: In 55 B.C.,
Rome's greatest general,
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Julius Caesar,
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decided to launch an attack
on the hostile Germanic tribes.
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He wanted to expand
and secure his empire
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into what is now
modern-day Germany,
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but how was he going
to get his whole army
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of 40,000 men across the river?
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Most leaders would
simply go around it,
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but Caesar wasn't going to let
anything stand in his way.
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- Caesar couldn't wait,
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and he wasn't willing to accept
that something couldn't be done.
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And in typical Caesar fashion,
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he was willing to try something
bold and audacious.
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narrator: Caesar's plan
was an engineering breakthrough
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and clearly demonstrated
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the strength
of Rome's power
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to their enemies.
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- This river had never
previously been bridged.
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This was a hugely
ambitious project
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at the very edge
of the Roman world.
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♪ ♪
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narrator:
Bridge building at that time
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normally took months,
if not years.
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Julius Caesar did it
in a matter of days.
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- Caesar was trying to cross
the Rhine at a point
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where it was
1/4 of a mile wide.
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So that's crossing a span
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that's as long as the
Empire State Building is tall.
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narrator:
The Rhine wasn't just wide.
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It was 30 feet deep
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with strong currents.
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♪ ♪
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These are military engineers
in today's British Army.
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They have modern, high-powered,
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mobile bridge-building
equipment.
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♪ ♪
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But Julius Caesar had
to start from scratch.
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- 40,000 Roman troops
start chopping down
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all the trees in the area.
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They didn't just need timber
for the bridge itself.
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They also needed timber
to create a huge floating crane
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and an enormous pile driver.
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narrator: The pile driver would
hammer in giant wooden stakes,
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which would give
the bridge stability
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and allow it hold the weight
of Caesar's massive army.
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This wasn't a standard
method of construction.
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It was revolutionary
engineering,
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and the Romans were
inventing it on the spot.
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With the piles in,
the bridge advanced the length
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of three school busses
every day.
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That's faster than modern
engineers can do.
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- The Germanic tribes were
on the other side of the river
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thinking they were safe,
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and you can just
imagine their horror
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when this bridge started
to creep towards to them.
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narrator: The bridge
took just ten days.
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It was long enough
and strong enough
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to hold the entire army.
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- It was a real incarnation
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of the might that was Rome.
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- Caesar was the master
of the publicity stunt.
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He marched across this bridge
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and said,
"Here I am.
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I can do whatever I want."
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Then he marched back
and tore it down.
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narrator:
The bridge was destroyed,
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but the point had been made.
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- It cemented Rome's reputation
as a military might
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more than any bloody battle
would have done.
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♪ ♪
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narrator: And the bridge
was an early example
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of using piles for support.
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♪ ♪
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Today, steel and concrete piles
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are the norm
for making things stable.
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Caesar and his engineers
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were thousands of years
ahead of their time.
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♪ ♪
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Like Caesar's bridge,
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the next Roman marvel
on our countdown
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was also the product
of the mighty Roman military.
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♪ ♪
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Shooting in at number nine,
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the repeating ballista,
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also known as the polybolos.
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- It's a Gatling gun.
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The same idea as today,
but 2,000 years ago.
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narrator: The Roman army
couldn't be matched.
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Organization, tactics,
weaponry.
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00:05:26,860 --> 00:05:29,127
Their weapon of choice
was the ballista,
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00:05:29,229 --> 00:05:30,829
a giant wooden crossbow
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that could launch bolts
a quarter of a mile.
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But they were always
looking to improve
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and to make their weapons
even more deadly.
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♪ ♪
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The Romans inherited
a new design from the Greeks,
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and took it to another level.
A repeater.
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This was the machine
gun of its day.
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00:05:51,552 --> 00:05:53,552
- The repeating ballista
could fire one bolt
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about every ten seconds,
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which doesn't sound like
that much until you realize
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that it actually tripled
the rate of fire
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that the Romans
had previously had.
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♪ ♪
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This was a devastating weapon.
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- It was a barrage.
It was a deadly rain of bolts,
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00:06:12,906 --> 00:06:14,573
and we're talking 1,500 years
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00:06:14,641 --> 00:06:16,541
before the first
artillery barrage.
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♪ ♪
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narrator: A repeating weapon
was sophisticated
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ancient engineering.
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It had a gravity-fed magazine,
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which would be constantly
dropping bolts down one by one.
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Winding the mechanism
pulls back the string,
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and the ballista fires
automatically.
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As long as the magazine
was kept loaded,
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this ancient machine gun
could fire continuously.
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It's known as a chain drive,
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and it was the first
in Western technology.
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- The Roman engineers
were the first people
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to master the chain drive.
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They were so ingenious.
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narrator:
Years ahead of its time,
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this technology
wouldn't be seen again
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until the 16th century
when Leonardo da Vinci
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supposedly reinvented it.
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The engineering genius
behind the polybolos
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was centuries
ahead of its time.
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- Amazingly, there's nothing
as effective on the battlefield
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for over 1,000 years.
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narrator: It was the pinnacle
of Roman military engineering,
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and the principles behind
the polybolos underpin
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our modern mechanics today.
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♪ ♪
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The development of technology
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has seen our cities advance
at a staggering pace,
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but our survival still
depends on the one basic need
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that hasn't changed
in millennia,
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water.
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Coming in at number eight,
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it's the Basilica Cistern
of Constantinople,
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modern day Istanbul.
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A giant underground reservoir
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providing a clean,
safe water supply.
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- Underneath modern-day Istanbul
there's a subterranean treasure.
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It's the Basilica Cistern.
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It was actually dug out
by 7,000 slaves
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working in appalling conditions
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so it's a wonder
of the medieval world,
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but it has a very dark history.
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♪ ♪
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narrator: The Basilica Cistern
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was built was not only to be
a source of water,
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but to form part
of the city's defenses.
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♪ ♪
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The cities of the Empire
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were a prime target
for invasion.
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They would be taken by force,
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and the best way to do that
was with siege warfare.
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- As long as we've had
cities and fortresses,
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we've had siege warfare.
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The defenders
have to wait it out.
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The attackers have to find a way
to starve them,
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thirst them,
or just make them give up.
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These things can take years,
and if you think about it,
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it really is just
a tactical chess game,
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and who's gonna win?
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It might take forever
to find out.
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♪ ♪
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narrator:
In ancient times,
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for a city to be secure
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and to withstand a siege,
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it took more than strong walls
and an army.
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What was needed most was
a safe supply of water.
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00:09:00,307 --> 00:09:02,140
- If there's no water
inside the city,
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then you can be held to ransom.
216
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narrator:
And having it underground
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meant it was protected.
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- As soon as you can secure
a water source inside the city,
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in a cistern, for example,
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you have got the upper hand.
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narrator: And that's exactly
what the Romans did
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at Constantinople.
223
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But this city's incredible
piece of engineering
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00:09:23,196 --> 00:09:24,930
lay hidden beneath the streets,
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00:09:25,032 --> 00:09:27,766
a secret for hundreds of years.
226
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How was it discovered?
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It's coming up next
on "Ancient Top 10."
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♪ ♪
229
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narrator:
This is Rome's Greatest Hits,
230
00:09:41,848 --> 00:09:44,382
amazing Roman feats
of engineering ranked
231
00:09:44,451 --> 00:09:47,352
by experts according to which
most changed the world.
232
00:09:47,454 --> 00:09:50,488
♪ ♪
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00:09:50,591 --> 00:09:54,492
The city of Istanbul
in modern-day Turkey.
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00:09:54,595 --> 00:09:57,495
In Roman times
it was called Constantinople
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and was capital
of the Eastern Roman Empire.
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00:10:00,200 --> 00:10:01,600
♪ ♪
237
00:10:01,702 --> 00:10:03,335
Its buildings concealed
a secret
238
00:10:03,437 --> 00:10:06,271
that laid undiscovered
for thousands of years,
239
00:10:06,373 --> 00:10:10,075
something so important it had
to be hidden deep underground.
240
00:10:10,177 --> 00:10:11,276
♪ ♪
241
00:10:11,378 --> 00:10:12,978
Number eight in our countdown.
242
00:10:13,080 --> 00:10:16,348
♪ ♪
243
00:10:16,450 --> 00:10:18,216
- 500 years ago in Istanbul
244
00:10:18,318 --> 00:10:19,784
there were people
in residential neighborhoods
245
00:10:19,886 --> 00:10:22,020
who were able to open up
the floorboards
246
00:10:22,122 --> 00:10:23,288
and the stones of their houses,
247
00:10:23,390 --> 00:10:24,789
lower cups and jugs down,
248
00:10:24,891 --> 00:10:26,191
and bring up water for drinking
249
00:10:26,293 --> 00:10:27,392
and washing their clothes.
250
00:10:27,494 --> 00:10:30,662
♪ ♪
251
00:10:30,764 --> 00:10:33,798
They launch an expedition,
they dug down deep,
252
00:10:33,900 --> 00:10:35,800
and they found
the Basilica Cisterns.
253
00:10:35,902 --> 00:10:37,302
♪ ♪
254
00:10:37,404 --> 00:10:39,070
narrator:
The Basilica Cistern,
255
00:10:39,172 --> 00:10:40,572
deep underground,
256
00:10:40,674 --> 00:10:43,808
but today open
for the public to view.
257
00:10:43,910 --> 00:10:47,512
Over 400 feet long
and 200 feet wide,
258
00:10:47,614 --> 00:10:49,814
the biggest and most
magnificent cistern
259
00:10:49,916 --> 00:10:52,283
in antiquity.
260
00:10:52,352 --> 00:10:56,788
It's as big as
an underground cathedral.
261
00:10:56,890 --> 00:10:57,922
narrator:
It's believed the Romans
262
00:10:58,025 --> 00:10:58,957
transferred this sculpture
263
00:10:59,059 --> 00:11:00,525
from another temple
264
00:11:00,627 --> 00:11:04,362
in order to keep
construction costs down.
265
00:11:04,464 --> 00:11:07,799
- The Romans were nothing
if not practical.
266
00:11:07,901 --> 00:11:09,801
narrator: The Basilica
Cistern wasn't the only
267
00:11:09,870 --> 00:11:12,137
sophisticated water system
in ancient times.
268
00:11:12,239 --> 00:11:16,141
♪ ♪
269
00:11:16,243 --> 00:11:19,110
In 73 AD,
there was an uprising of Jews
270
00:11:19,212 --> 00:11:20,979
against the Romans.
271
00:11:21,081 --> 00:11:23,848
Despite being surrounded
and their supplies cut off,
272
00:11:23,950 --> 00:11:26,451
a rebel force was able
to hold out for months
273
00:11:26,553 --> 00:11:28,453
in the mountain fortress
of Masada,
274
00:11:28,555 --> 00:11:31,389
in what is modern-day Israel,
275
00:11:31,491 --> 00:11:33,391
thanks to a cistern providing
276
00:11:33,493 --> 00:11:36,728
a ready supply of fresh water.
277
00:11:36,830 --> 00:11:38,730
And Alexandria in ancient Egypt
278
00:11:38,832 --> 00:11:41,032
had a remarkable cistern
under the city,
279
00:11:41,101 --> 00:11:44,536
making it a major stronghold.
280
00:11:44,638 --> 00:11:46,971
But the water supply
delivered to Constantinople
281
00:11:47,074 --> 00:11:50,341
by the Basilica Cistern
was unmatched.
282
00:11:50,444 --> 00:11:52,243
It was the largest
and most impressive
283
00:11:52,345 --> 00:11:54,179
in the ancient world.
284
00:11:54,281 --> 00:11:55,580
♪ ♪
285
00:11:55,682 --> 00:11:58,016
- The Basilica Cistern
was huge.
286
00:11:58,118 --> 00:12:01,753
It stored 22 million
gallons of water,
287
00:12:01,855 --> 00:12:06,024
so that gave Constantinople
its strength and its security.
288
00:12:06,126 --> 00:12:08,693
It meant the city
could not just survive,
289
00:12:08,795 --> 00:12:10,261
but thrive.
290
00:12:10,363 --> 00:12:12,030
narrator:
This engineering marvel
291
00:12:12,132 --> 00:12:15,667
would not be bettered
for 1,500 years.
292
00:12:15,769 --> 00:12:18,870
The Romans used advanced
technology and engineering
293
00:12:18,972 --> 00:12:22,006
to ensure that the cistern
was built to last.
294
00:12:22,109 --> 00:12:25,443
- The walls of the Basilica
Cistern are 12 feet thick
295
00:12:25,545 --> 00:12:27,512
and they're lined
with waterproof cement,
296
00:12:27,614 --> 00:12:29,414
and it still works.
297
00:12:29,516 --> 00:12:32,183
It's not a ruin.
It still functions.
298
00:12:32,285 --> 00:12:33,651
It still holds water.
299
00:12:33,754 --> 00:12:35,386
narrator:
Thanks in part to
300
00:12:35,489 --> 00:12:37,288
this incredible piece
of Roman engineering,
301
00:12:37,390 --> 00:12:38,690
Constantinople was able to
302
00:12:38,792 --> 00:12:40,425
withstand repeated sieges
303
00:12:40,527 --> 00:12:43,628
for nearly 1,000 years
to overtake Rome
304
00:12:43,697 --> 00:12:46,798
and become the greatest city
in the world at the time.
305
00:12:46,900 --> 00:12:49,300
♪ ♪
306
00:12:49,436 --> 00:12:50,969
Control of water
was also behind
307
00:12:51,071 --> 00:12:53,605
the next engineering great.
308
00:12:53,707 --> 00:12:55,607
At number seven...
309
00:12:55,709 --> 00:12:58,877
♪ ♪
310
00:12:58,979 --> 00:13:00,712
The Nemi Tunnel.
311
00:13:00,814 --> 00:13:02,714
♪ ♪
312
00:13:02,816 --> 00:13:06,451
19 miles south of Rome
is a sacred lake,
313
00:13:06,553 --> 00:13:07,886
Lake Nemi.
314
00:13:07,988 --> 00:13:09,387
♪ ♪
315
00:13:09,489 --> 00:13:10,889
In the early Roman period,
316
00:13:10,991 --> 00:13:13,424
the lake was prone to flooding.
317
00:13:13,527 --> 00:13:16,494
At the lakeside was a temple
to the goddess Diana,
318
00:13:16,596 --> 00:13:20,932
and allowing her temple to
flood was simply unacceptable.
319
00:13:21,034 --> 00:13:24,302
The Romans came up
with an extraordinary solution,
320
00:13:24,404 --> 00:13:27,572
to build a tunnel
through a mountain.
321
00:13:27,674 --> 00:13:29,007
- The Nemi Tunnel was over
322
00:13:29,109 --> 00:13:32,043
a mile long
through a solid mountain.
323
00:13:32,145 --> 00:13:36,247
This is ancient engineering
at its most sublime.
324
00:13:36,349 --> 00:13:39,250
♪ ♪
325
00:13:39,352 --> 00:13:42,387
narrator: The tunnel was
built around 500 BC.
326
00:13:42,489 --> 00:13:44,389
♪ ♪
327
00:13:44,491 --> 00:13:46,558
Constructing any kind
of tunnel back then
328
00:13:46,660 --> 00:13:48,259
was an extraordinary feat,
329
00:13:48,361 --> 00:13:50,395
let alone one this long.
330
00:13:50,497 --> 00:13:52,530
♪ ♪
331
00:13:52,632 --> 00:13:57,235
And 2,500 years later,
it's still intact.
332
00:13:57,337 --> 00:13:59,938
- The Nemi Tunnels
were actually dug out by hand.
333
00:14:00,040 --> 00:14:02,507
This was harsh,
horrendous manual labor,
334
00:14:02,609 --> 00:14:03,942
but they persevered to the end
335
00:14:04,044 --> 00:14:07,212
and dug out a staggering
5,000 feet.
336
00:14:07,314 --> 00:14:10,081
narrator: The Roman workers
only had simple tools
337
00:14:10,183 --> 00:14:13,084
and just the light
of small oil lamps.
338
00:14:13,186 --> 00:14:16,487
In the tunnel it was dark,
cold, and wet,
339
00:14:16,556 --> 00:14:19,090
but this tunnel was built
with such accuracy,
340
00:14:19,192 --> 00:14:23,595
even modern engineers
would struggle to match it.
341
00:14:23,697 --> 00:14:28,433
Today, we use lasers to tunnel
in a straight line.
342
00:14:28,535 --> 00:14:32,070
Unbelievably, the Romans
started digging from both sides
343
00:14:32,172 --> 00:14:33,605
of the mountain at once,
344
00:14:33,707 --> 00:14:36,941
and, somehow,
met partway through.
345
00:14:37,010 --> 00:14:38,543
- It's absolutely incredible.
346
00:14:38,645 --> 00:14:41,379
How could they build this
without modern building
347
00:14:41,481 --> 00:14:43,715
and surveying equipment?
348
00:14:43,817 --> 00:14:45,950
narrator: Two tunneling teams
worked independently
349
00:14:46,052 --> 00:14:47,986
with incredible precision.
350
00:14:48,088 --> 00:14:49,454
♪ ♪
351
00:14:49,556 --> 00:14:51,589
When they met,
the paths they dug
352
00:14:51,691 --> 00:14:53,958
were within ten feet
of each other.
353
00:14:54,060 --> 00:14:57,562
- Both sides meeting with pretty
impressive accuracy,
354
00:14:57,664 --> 00:15:01,566
and it travels across
an impossibly gentle gradient.
355
00:15:01,668 --> 00:15:03,067
♪ ♪
356
00:15:03,169 --> 00:15:04,736
- The tunnel's over
a mile long,
357
00:15:04,838 --> 00:15:06,504
and in that entire distance,
358
00:15:06,606 --> 00:15:09,574
it drops by just 41 feet.
359
00:15:09,676 --> 00:15:14,245
That's an average gradient
drop of less than 1%.
360
00:15:14,347 --> 00:15:17,949
narrator: Even today, we don't
know exactly how they did it.
361
00:15:18,051 --> 00:15:20,652
It could be an example
of skills and technology
362
00:15:20,754 --> 00:15:23,421
that have been lost to time.
363
00:15:23,523 --> 00:15:25,957
This workmanship
has kept the tunnel in use
364
00:15:26,059 --> 00:15:28,159
right up to recent times.
365
00:15:28,261 --> 00:15:29,694
♪ ♪
366
00:15:29,796 --> 00:15:31,195
In the 1930s,
367
00:15:31,264 --> 00:15:33,131
the Italian dictator Mussolini
368
00:15:33,233 --> 00:15:35,333
used it to drain Lake Nemi.
369
00:15:35,435 --> 00:15:38,536
He wanted to recover
what lay at the bottom,
370
00:15:38,638 --> 00:15:40,138
the priceless remains
of two ships
371
00:15:40,240 --> 00:15:43,875
built for the Roman emperor
Caligula.
372
00:15:43,977 --> 00:15:45,710
The lake gave up
its secrets,
373
00:15:45,812 --> 00:15:48,012
but the tunnel's
impressive construction
374
00:15:48,114 --> 00:15:49,981
still remains a mystery.
375
00:15:50,083 --> 00:15:51,983
♪ ♪
376
00:15:52,085 --> 00:15:55,320
Our next invention uncovers
the dark side of the Romans,
377
00:15:55,422 --> 00:15:57,722
and it only came to light
after the discovery
378
00:15:57,824 --> 00:15:59,691
of a mysterious ancient wheel,
379
00:15:59,826 --> 00:16:03,328
the likes of which have
never been seen before.
380
00:16:03,430 --> 00:16:06,531
It led historians
to a Roman underground hell
381
00:16:06,633 --> 00:16:09,534
that would claim
the lives of countless slaves.
382
00:16:09,636 --> 00:16:13,771
♪ ♪
383
00:16:16,810 --> 00:16:18,876
narrator: This is
"Ancient Top Ten's"
384
00:16:18,979 --> 00:16:22,113
countdown of the most amazing
feats of Roman engineering,
385
00:16:22,215 --> 00:16:26,117
shining a light on technology
that would change the world.
386
00:16:26,219 --> 00:16:27,618
Rolling in at number six...
387
00:16:27,721 --> 00:16:30,488
[dramatic music]
388
00:16:30,590 --> 00:16:31,990
Is the underground hell
389
00:16:32,092 --> 00:16:34,425
of the silver mine
at Rio Tinto.
390
00:16:34,527 --> 00:16:36,094
♪ ♪
391
00:16:36,162 --> 00:16:38,496
The Roman Empire spread
all the way from Britain
392
00:16:38,598 --> 00:16:40,231
to the Middle East,
393
00:16:40,333 --> 00:16:43,401
but it was here,
in the hills of southern Spain,
394
00:16:43,503 --> 00:16:45,403
that 100 years ago,
395
00:16:45,505 --> 00:16:49,440
the remains of this strange
wooden wheel were found.
396
00:16:49,509 --> 00:16:51,009
What could it be?
397
00:16:51,111 --> 00:16:53,411
It was soon discovered
to be Roman,
398
00:16:53,513 --> 00:16:56,814
and it was over
2,000 years old.
399
00:16:56,916 --> 00:16:59,050
- What the experts soon
realized was that
400
00:16:59,152 --> 00:17:01,753
they discovered
a giant water wheel
401
00:17:01,855 --> 00:17:05,423
14 1/2 feet in diameter.
402
00:17:05,525 --> 00:17:08,659
And the most amazing thing,
it hadn't been buried.
403
00:17:08,762 --> 00:17:11,863
It was supposed
to be underground.
404
00:17:11,931 --> 00:17:14,232
narrator: This water wheel
was part of the machinery
405
00:17:14,334 --> 00:17:15,600
of an ancient silver mine
406
00:17:15,702 --> 00:17:19,203
known as Rio Tinto.
407
00:17:19,305 --> 00:17:20,905
Precious metals
like silver and gold
408
00:17:21,007 --> 00:17:23,207
were crucial
for the Romans.
409
00:17:23,309 --> 00:17:25,843
Their huge empire
needed paying for.
410
00:17:25,945 --> 00:17:28,713
Massive building projects,
the military,
411
00:17:28,815 --> 00:17:30,281
and their administration.
412
00:17:30,350 --> 00:17:33,384
Somehow,
this all needed to be funded.
413
00:17:33,486 --> 00:17:35,853
- The 60 million citizens
of the Roman Empire
414
00:17:35,955 --> 00:17:37,622
needed a currency to trade in.
415
00:17:37,724 --> 00:17:41,626
To get that currency,
they needed pure silver.
416
00:17:41,728 --> 00:17:43,227
narrator:
In order to get this silver,
417
00:17:43,329 --> 00:17:46,230
they constructed
underground mines,
418
00:17:46,332 --> 00:17:47,799
but they had a problem.
419
00:17:47,901 --> 00:17:49,467
The mines were prone
to flooding
420
00:17:49,569 --> 00:17:51,936
from subsurface water supplies,
421
00:17:52,038 --> 00:17:55,640
so the Romans constructed
huge water wheels.
422
00:17:55,742 --> 00:17:59,377
They were used to drain
the water away from the mine.
423
00:17:59,479 --> 00:18:00,812
How was this done?
424
00:18:00,914 --> 00:18:02,580
Buy the feet of slaves.
425
00:18:02,682 --> 00:18:06,451
- Huge underground water wheels
being walked on by slaves.
426
00:18:06,553 --> 00:18:08,086
It's crazy, isn't it?
427
00:18:08,221 --> 00:18:10,488
Would you have liked
to be the Roman engineer
428
00:18:10,590 --> 00:18:12,090
who floated that idea?
429
00:18:12,192 --> 00:18:15,326
They must have thought
he was nuts.
430
00:18:15,428 --> 00:18:17,295
narrator: Incredibly,
there were eight pairs
431
00:18:17,397 --> 00:18:20,398
of wheels raising the water
from one cavern to the next
432
00:18:20,500 --> 00:18:22,834
and up out of the mine.
433
00:18:22,936 --> 00:18:24,936
Once again,
the Romans were using
434
00:18:25,038 --> 00:18:29,073
their engineering genius
to overcome nature.
435
00:18:29,175 --> 00:18:31,509
- The whole system
could lift water
436
00:18:31,611 --> 00:18:35,847
the height of
a ten-story building.
437
00:18:35,949 --> 00:18:38,850
narrator: These astonishing
wheels never stopped.
438
00:18:38,952 --> 00:18:42,286
They were worked
24 hours a day.
439
00:18:42,388 --> 00:18:44,822
- It's estimated that
one slave could raise
440
00:18:44,924 --> 00:18:47,291
21 gallons of water per minute,
441
00:18:47,393 --> 00:18:50,928
so that means the whole system
could lift 180,000 gallons
442
00:18:51,030 --> 00:18:54,198
of water every day.
443
00:18:54,300 --> 00:18:57,602
narrator: Most of these slaves
didn't live much over a year,
444
00:18:57,704 --> 00:19:00,371
and when they died,
the Romans didn't even bother
445
00:19:00,473 --> 00:19:03,374
taking their bodies
to the surface.
446
00:19:03,476 --> 00:19:05,743
- This worked out fantastic
for the Romans,
447
00:19:05,845 --> 00:19:07,478
but not so well for the slaves.
448
00:19:07,580 --> 00:19:11,082
It's impossible to imagine
the horrifying lives
449
00:19:11,184 --> 00:19:14,552
that the slaves endured
down in the mines.
450
00:19:14,654 --> 00:19:16,154
narrator:
Sacrificing lives
451
00:19:16,256 --> 00:19:18,289
for an incredible
feat of engineering.
452
00:19:18,391 --> 00:19:21,292
This was typical
of the Romans.
453
00:19:21,361 --> 00:19:23,561
Without mining
the riches of Rio Tinto,
454
00:19:23,663 --> 00:19:26,597
the empire would never have
been able to expand so far.
455
00:19:26,699 --> 00:19:28,599
♪ ♪
456
00:19:28,701 --> 00:19:29,934
A growing empire
brought with it
457
00:19:30,036 --> 00:19:31,602
a growing population.
458
00:19:31,704 --> 00:19:33,838
They all needed to be fed,
459
00:19:33,940 --> 00:19:36,307
so the Romans used technology
460
00:19:36,409 --> 00:19:38,910
to do it on a massive scale.
461
00:19:39,012 --> 00:19:43,281
Next in our countdown is
an extraordinary food factory.
462
00:19:43,383 --> 00:19:46,417
It could be described as
Roman fast food.
463
00:19:46,519 --> 00:19:47,852
Coming in at number five...
464
00:19:47,954 --> 00:19:50,855
♪ ♪
465
00:19:50,957 --> 00:19:53,624
The amazing water mills
of Barbegal.
466
00:19:53,726 --> 00:19:55,626
♪ ♪
467
00:19:55,728 --> 00:19:57,962
This is Barbegal
in southern France,
468
00:19:58,064 --> 00:19:59,830
near the city of Arles.
469
00:19:59,933 --> 00:20:01,832
♪ ♪
470
00:20:01,935 --> 00:20:04,402
In the 1940s,
experts realized
471
00:20:04,470 --> 00:20:06,537
that these strange ruins
were the remains
472
00:20:06,639 --> 00:20:08,839
of something
truly spectacular...
473
00:20:08,942 --> 00:20:11,209
♪ ♪
474
00:20:11,311 --> 00:20:14,178
A series of water mills
producing huge amounts
475
00:20:14,280 --> 00:20:16,047
of flour thousands of years
476
00:20:16,149 --> 00:20:19,050
before the industrial
revolution.
477
00:20:19,152 --> 00:20:23,487
To this day, there has never
been anything else like it.
478
00:20:23,590 --> 00:20:28,326
- It's an industrial
super factory, and it's Roman.
479
00:20:28,428 --> 00:20:29,961
narrator: Water mills
were already used
480
00:20:30,063 --> 00:20:32,697
in food production
individually.
481
00:20:32,799 --> 00:20:36,734
The ancient Chinese had them
and the Greeks too.
482
00:20:36,803 --> 00:20:40,171
But mills linked together
was something completely new.
483
00:20:40,240 --> 00:20:43,808
It was a huge
technological leap.
484
00:20:43,910 --> 00:20:47,211
- They didn't just have
one water wheel, they had 16.
485
00:20:47,313 --> 00:20:51,649
This really was the world's
first mega factory.
486
00:20:51,751 --> 00:20:53,551
- The water flowed through
a series of mills
487
00:20:53,653 --> 00:20:55,319
powering each one in turn.
488
00:20:55,421 --> 00:20:57,655
Now, that's only
a drop of 65 feet,
489
00:20:57,757 --> 00:20:59,490
but each water mill
is going to be receiving
490
00:20:59,592 --> 00:21:02,159
33 gallons of water
every second.
491
00:21:02,262 --> 00:21:04,996
That's a huge energy output.
492
00:21:05,098 --> 00:21:06,931
narrator: Unlike
most conventional water wheels
493
00:21:07,033 --> 00:21:08,733
which were powered
by the flow of a river
494
00:21:08,835 --> 00:21:11,068
at the bottom
of the wheel,
495
00:21:11,170 --> 00:21:13,371
these were overshot
water wheels,
496
00:21:13,473 --> 00:21:15,773
the difference being that
they were powered by the water
497
00:21:15,875 --> 00:21:18,042
dropping on the wheel
from above,
498
00:21:18,144 --> 00:21:21,279
a much more powerful method.
499
00:21:21,381 --> 00:21:23,080
The construction
of this new system
500
00:21:23,182 --> 00:21:25,549
was a huge technical challenge.
501
00:21:25,652 --> 00:21:27,285
- To power these water wheels,
502
00:21:27,387 --> 00:21:30,855
the Romans actually diverted
a nearby aqueduct.
503
00:21:30,957 --> 00:21:35,393
♪ ♪
504
00:21:35,495 --> 00:21:37,128
And even more impressively,
505
00:21:37,196 --> 00:21:39,530
they cut a channel
through the solid rock
506
00:21:39,632 --> 00:21:42,266
of a mountainside
to create a passage
507
00:21:42,368 --> 00:21:44,568
for the water
to reach the wheels.
508
00:21:44,671 --> 00:21:47,571
♪ ♪
509
00:21:47,674 --> 00:21:49,206
- Enough flour was made there
510
00:21:49,309 --> 00:21:53,311
to produce 9,000 loaves of bread
every single day.
511
00:21:53,413 --> 00:21:57,148
narrator: That's 4 1/2 tons
of bread daily.
512
00:21:57,250 --> 00:21:59,450
This was enough to feed
the Roman troops nearby
513
00:21:59,552 --> 00:22:03,621
as well as the recently
conquered Gauls in Arles.
514
00:22:03,723 --> 00:22:05,656
If their new citizens
were fed and watered,
515
00:22:05,758 --> 00:22:09,660
the Romans knew they would
be less likely to rebel.
516
00:22:09,762 --> 00:22:11,629
As well as grinding flour,
517
00:22:11,731 --> 00:22:14,065
the mills could be used
for other purposes too,
518
00:22:14,167 --> 00:22:17,001
such as powering
mechanical saws.
519
00:22:17,136 --> 00:22:18,936
Barbegal might well
have been the world's
520
00:22:19,038 --> 00:22:22,239
first multipurpose factory.
521
00:22:22,342 --> 00:22:24,275
It's been described
as the greatest
522
00:22:24,377 --> 00:22:26,577
know concentration
of mechanical power
523
00:22:26,679 --> 00:22:28,846
in the ancient world.
524
00:22:28,948 --> 00:22:36,420
This was an industrial
revolution 2,000 years ago.
525
00:22:39,225 --> 00:22:40,991
narrator:
This is "Ancient Top Ten's"
526
00:22:41,094 --> 00:22:44,829
Rome's Greatest Hits,
Roman engineering breakthroughs
527
00:22:44,931 --> 00:22:47,832
ranked according to
their effect on the world.
528
00:22:47,934 --> 00:22:52,503
Number ten was Caesar's amazing
bridge across the Rhine.
529
00:22:52,605 --> 00:22:56,807
At number nine, the incredible
repeating ballista.
530
00:22:56,909 --> 00:23:01,045
Number eight was the
magnificent Basilica Cisterns.
531
00:23:01,147 --> 00:23:04,448
And number seven,
the intriguing Nemi Tunnels.
532
00:23:04,550 --> 00:23:08,552
Six was the horror that was
the mine at Rio Tinto.
533
00:23:08,654 --> 00:23:10,221
And number five,
534
00:23:10,323 --> 00:23:13,724
astonishing ancient
industry at Barbegal.
535
00:23:13,826 --> 00:23:17,128
But next in our countdown
is an engineering breakthrough
536
00:23:17,230 --> 00:23:18,629
that was bigger still.
537
00:23:18,731 --> 00:23:20,698
It transformed the face
of the towns
538
00:23:20,800 --> 00:23:23,701
and cities
of the Western world.
539
00:23:23,803 --> 00:23:25,202
At number four...
540
00:23:25,304 --> 00:23:28,205
[dramatic music]
541
00:23:28,307 --> 00:23:30,708
Elevating the Romans
to new heights,
542
00:23:30,810 --> 00:23:35,079
it's the ingenious crane,
the polyspastos.
543
00:23:35,181 --> 00:23:39,049
Building in the ancient world
was hugely labor-intensive.
544
00:23:39,152 --> 00:23:42,186
Every massive block of
the mighty Egyptian pyramids
545
00:23:42,288 --> 00:23:45,189
was hauled up
by manpower alone.
546
00:23:45,291 --> 00:23:48,959
But Roman engineering
was to change building forever.
547
00:23:49,028 --> 00:23:52,329
They invented the ultimate
lifting machine.
548
00:23:52,432 --> 00:23:55,232
- The polyspastos was
a massive breakthrough.
549
00:23:55,334 --> 00:23:57,601
It allowed the Romans
to build bigger and faster
550
00:23:57,703 --> 00:24:00,237
than they'd ever done before.
551
00:24:00,339 --> 00:24:02,206
narrator:
This revolutionary machine
552
00:24:02,308 --> 00:24:05,876
was many pulleys joined
together into a crane,
553
00:24:05,978 --> 00:24:08,012
hence the name polyspastos,
554
00:24:08,114 --> 00:24:10,448
meaning multiple pulleys.
555
00:24:10,550 --> 00:24:14,718
The amount that one crane
could lift increased massively
556
00:24:14,821 --> 00:24:17,388
to over 3 tons.
557
00:24:17,490 --> 00:24:19,089
- This crane allowed each person
558
00:24:19,192 --> 00:24:20,758
using it to shift 60 times
559
00:24:20,860 --> 00:24:22,760
as much as they would otherwise.
560
00:24:22,862 --> 00:24:25,763
Roman engineering
went into overdrive.
561
00:24:25,865 --> 00:24:27,765
♪ ♪
562
00:24:27,867 --> 00:24:29,867
- Incredible buildings
and monuments,
563
00:24:29,969 --> 00:24:31,435
how are they made possible?
564
00:24:31,537 --> 00:24:33,204
With this amazing crane.
565
00:24:33,306 --> 00:24:35,272
♪ ♪
566
00:24:35,374 --> 00:24:39,076
The polyspastos crane
built Rome.
567
00:24:39,178 --> 00:24:40,978
- But the Roman engineers
didn't stop there.
568
00:24:41,080 --> 00:24:42,813
They took things
one step further.
569
00:24:42,915 --> 00:24:44,415
♪ ♪
570
00:24:44,517 --> 00:24:46,083
narrator:
The crane's original design
571
00:24:46,185 --> 00:24:48,152
used a capstan
to lift the arm,
572
00:24:48,254 --> 00:24:51,121
which is a horizontal
wheel turned by hand.
573
00:24:51,224 --> 00:24:53,724
But again, the Romans
saw the opportunity
574
00:24:53,826 --> 00:24:56,460
to make their invention
more powerful.
575
00:24:56,562 --> 00:24:59,063
- They swapped out the capstan
for a treadwheel,
576
00:24:59,165 --> 00:25:02,066
which was walked by slaves,
577
00:25:02,168 --> 00:25:05,469
thereby doubling the lifting
capacity of the crane.
578
00:25:05,571 --> 00:25:07,838
If you can lift more,
you can build bigger.
579
00:25:07,940 --> 00:25:09,607
♪ ♪
580
00:25:09,709 --> 00:25:12,610
- It may be even possible
that several polyspastos cranes
581
00:25:12,712 --> 00:25:15,746
were used together in one big
interlocked mechanism.
582
00:25:15,848 --> 00:25:18,349
And if that's the case,
imagine the lifting power.
583
00:25:18,451 --> 00:25:19,583
The sky is the limit.
584
00:25:19,685 --> 00:25:21,418
♪ ♪
585
00:25:21,521 --> 00:25:23,387
- They basically
liked to show off.
586
00:25:23,489 --> 00:25:24,922
Not only did they want to prove
587
00:25:25,024 --> 00:25:26,924
that they had mastery
over the natural world,
588
00:25:27,026 --> 00:25:30,094
they also wanted to
intimidate their enemies.
589
00:25:30,196 --> 00:25:33,030
♪ ♪
590
00:25:33,132 --> 00:25:35,099
narrator: Nothing changed
the face of the empire
591
00:25:35,201 --> 00:25:38,302
as much as
this remarkable crane.
592
00:25:38,404 --> 00:25:40,905
And the monster
lifting machines of today
593
00:25:40,973 --> 00:25:42,773
and the skylines
that they've built
594
00:25:42,875 --> 00:25:46,176
have all evolved from this
groundbreaking device.
595
00:25:46,279 --> 00:25:51,181
♪ ♪
596
00:25:51,284 --> 00:25:53,717
Our next Roman breakthrough
was a monumental
597
00:25:53,819 --> 00:25:56,287
engineering project
at ground level.
598
00:25:56,389 --> 00:25:57,521
At number three...
599
00:25:57,623 --> 00:26:00,791
♪ ♪
600
00:26:00,893 --> 00:26:03,827
The extraordinary and
revolutionary system
601
00:26:03,930 --> 00:26:05,996
of Roman roads.
602
00:26:06,098 --> 00:26:08,999
♪ ♪
603
00:26:09,101 --> 00:26:13,003
Before the Romans,
people used simple tracks,
604
00:26:13,105 --> 00:26:15,139
but the Romans wanted
to march their armies
605
00:26:15,241 --> 00:26:16,874
across their empire,
606
00:26:16,976 --> 00:26:20,077
not to be constrained
by their environment.
607
00:26:20,146 --> 00:26:23,013
They knew a well-built
and reliable system of roads
608
00:26:23,115 --> 00:26:27,151
would be good for trade,
and for their military.
609
00:26:27,253 --> 00:26:29,920
Road building
went into overdrive.
610
00:26:30,022 --> 00:26:33,657
- There are over 250,000 miles
611
00:26:33,759 --> 00:26:35,893
of known Roman roads.
612
00:26:35,995 --> 00:26:37,661
There are probably
actually even more
613
00:26:37,763 --> 00:26:39,663
that we simply don't know about.
614
00:26:39,765 --> 00:26:40,898
That is more
615
00:26:41,000 --> 00:26:43,233
than the distance to the moon.
616
00:26:43,336 --> 00:26:45,069
♪ ♪
617
00:26:45,171 --> 00:26:46,437
narrator:
No civilization since
618
00:26:46,539 --> 00:26:49,440
has ever built on such a scale.
619
00:26:49,542 --> 00:26:52,042
372 great roads connected
620
00:26:52,144 --> 00:26:55,613
the empire's 113 provinces.
621
00:26:55,715 --> 00:26:59,350
- In those days, the saying
"all roads lead to Rome"
622
00:26:59,452 --> 00:27:00,918
was more than just a saying.
623
00:27:01,020 --> 00:27:03,520
It was the literal truth.
624
00:27:03,623 --> 00:27:05,356
narrator:
On a newly constructed road,
625
00:27:05,458 --> 00:27:09,460
a Roman legion could march
about 20 miles a day.
626
00:27:09,562 --> 00:27:12,262
The mile itself is
a Roman invention.
627
00:27:12,365 --> 00:27:15,699
It was created to measure
1,000 steps of the army.
628
00:27:15,801 --> 00:27:18,335
narrator: The Romans created
their roads with precision
629
00:27:18,437 --> 00:27:20,304
and incredibly
modern techniques.
630
00:27:20,406 --> 00:27:23,073
- The most amazing thing
about Roman roads
631
00:27:23,175 --> 00:27:24,908
is their construction.
632
00:27:24,977 --> 00:27:29,113
That's what makes them such
incredible feats of engineering.
633
00:27:29,215 --> 00:27:32,149
narrator:
And they were built to last.
634
00:27:32,218 --> 00:27:34,451
- There were large stones
at the bottom,
635
00:27:34,553 --> 00:27:36,186
laid up with smaller stones
636
00:27:36,288 --> 00:27:39,990
and then gravel
hard packed on top.
637
00:27:40,092 --> 00:27:41,692
narrator: They're famous
for being straight
638
00:27:41,794 --> 00:27:43,360
because it's
the most efficient way
639
00:27:43,462 --> 00:27:45,729
to reach your destination.
640
00:27:45,831 --> 00:27:49,166
But straight roads were also
a sign of Roman power.
641
00:27:49,268 --> 00:27:51,368
They built them straight
because they could,
642
00:27:51,470 --> 00:27:54,471
whatever the obstacles,
643
00:27:54,573 --> 00:27:55,906
and much of the huge network
644
00:27:56,008 --> 00:27:59,643
can still be seen to this day.
645
00:27:59,745 --> 00:28:01,645
- The ingenuity
of their design,
646
00:28:01,747 --> 00:28:04,014
and the sheer amount of mileage
647
00:28:04,116 --> 00:28:06,884
that they covered, means that
the Roman road system
648
00:28:06,986 --> 00:28:10,654
has to have its place
in any Roman top ten.
649
00:28:10,756 --> 00:28:12,256
narrator:
Roads were the glue
650
00:28:12,358 --> 00:28:13,924
that held the Roman Empire
together,
651
00:28:14,026 --> 00:28:16,694
and they still connect
towns and cities today.
652
00:28:16,796 --> 00:28:18,195
♪ ♪
653
00:28:18,297 --> 00:28:20,097
The Romans used
a secret ingredient
654
00:28:20,199 --> 00:28:22,066
in their road construction,
655
00:28:22,168 --> 00:28:25,602
something that transformed
engineering and architecture.
656
00:28:25,705 --> 00:28:27,771
It's a 2,000-year-old
technology
657
00:28:27,873 --> 00:28:29,707
that most would think
was only invented
658
00:28:29,809 --> 00:28:32,109
in the past few hundred years.
659
00:28:32,211 --> 00:28:34,211
Today we take it for granted.
660
00:28:34,313 --> 00:28:36,046
It's all around us
661
00:28:36,148 --> 00:28:38,615
and this extraordinary
revolutionary breakthrough
662
00:28:38,718 --> 00:28:41,852
is coming up next
as our number two
663
00:28:41,954 --> 00:28:44,054
on "Ancient Top Ten."
664
00:28:44,156 --> 00:28:47,157
♪ ♪
665
00:28:49,929 --> 00:28:53,363
narrator: Roman construction
that changed the world.
666
00:28:53,466 --> 00:28:56,734
This is Rome's Greatest Hits,
667
00:28:56,836 --> 00:28:59,770
the most incredible feats
of Roman engineering.
668
00:28:59,839 --> 00:29:01,105
[dramatic music]
669
00:29:01,207 --> 00:29:02,272
Next on our list is
670
00:29:02,374 --> 00:29:03,741
an engineering breakthrough
671
00:29:03,843 --> 00:29:05,042
that revolutionized
construction
672
00:29:05,144 --> 00:29:06,910
in the ancient world,
673
00:29:06,979 --> 00:29:08,612
and thousands of years later,
674
00:29:08,714 --> 00:29:11,548
our modern engineering
depends on it.
675
00:29:11,650 --> 00:29:12,750
At number two...
676
00:29:12,852 --> 00:29:15,185
♪ ♪
677
00:29:15,287 --> 00:29:17,521
Is concrete.
678
00:29:17,590 --> 00:29:18,555
- Concrete.
679
00:29:18,657 --> 00:29:21,058
The Romans invented concrete
680
00:29:21,160 --> 00:29:23,927
2,000 years ago.
681
00:29:24,029 --> 00:29:27,631
We think of concrete
as a modern discovery.
682
00:29:27,733 --> 00:29:30,367
But in fact, it's reinvention.
683
00:29:30,469 --> 00:29:32,970
It's rediscovery.
684
00:29:33,072 --> 00:29:36,640
narrator: The Pantheon
in the middle of Rome,
685
00:29:36,709 --> 00:29:40,277
one of the most astonishing
buildings ever built.
686
00:29:40,379 --> 00:29:44,148
It's 2,000 years old
and still intact,
687
00:29:44,250 --> 00:29:46,083
and its huge dome
688
00:29:46,185 --> 00:29:49,520
made entirely of
unreinforced concrete.
689
00:29:49,588 --> 00:29:51,054
♪ ♪
690
00:29:51,157 --> 00:29:53,423
- The Pantheon was built
as a temple to honor
691
00:29:53,526 --> 00:29:54,925
all of the Roman gods.
692
00:29:55,027 --> 00:29:57,761
It actually has
the largest unreinforced
693
00:29:57,863 --> 00:29:59,763
concrete dome in the world.
694
00:29:59,865 --> 00:30:02,099
The fact that
this is still standing today
695
00:30:02,234 --> 00:30:05,936
just stands as a testament
to the awesome engineering minds
696
00:30:06,038 --> 00:30:08,172
of the ancient Romans.
697
00:30:08,240 --> 00:30:09,373
narrator:
The beauty of concrete
698
00:30:09,475 --> 00:30:10,941
is that it can be poured
699
00:30:11,043 --> 00:30:13,410
and molded into blocks
of any shape.
700
00:30:13,512 --> 00:30:17,080
The Romans could make arches,
701
00:30:17,183 --> 00:30:20,584
vaults, and domes.
702
00:30:20,686 --> 00:30:23,487
This was an architectural
revolution,
703
00:30:23,589 --> 00:30:25,022
and the Pantheon
is the pinnacle
704
00:30:25,124 --> 00:30:28,125
of Roman concrete construction.
705
00:30:28,227 --> 00:30:31,028
- The dome of the Pantheon
is a fantastic example
706
00:30:31,130 --> 00:30:32,763
of how good the Romans were
707
00:30:32,865 --> 00:30:34,932
at building in concrete.
708
00:30:35,034 --> 00:30:38,135
It's 142 feet in diameter
709
00:30:38,237 --> 00:30:40,304
with no columns
to support the dome.
710
00:30:40,406 --> 00:30:43,540
That is 50% bigger
than the dome
711
00:30:43,642 --> 00:30:46,276
of the Capitol Building
in Washington.
712
00:30:46,378 --> 00:30:48,278
♪ ♪
713
00:30:48,380 --> 00:30:50,314
- The diameter of the Pantheon
is the same
714
00:30:50,416 --> 00:30:51,982
is the height of the structure.
715
00:30:52,084 --> 00:30:54,017
It's an absolutely
enormous space.
716
00:30:54,119 --> 00:30:57,487
You could hold over 5,000
people inside the Pantheon.
717
00:30:57,556 --> 00:30:59,323
It's absolutely amazing.
718
00:30:59,425 --> 00:31:03,160
♪ ♪
719
00:31:03,262 --> 00:31:05,462
- Roman concrete technology
was incredible.
720
00:31:05,564 --> 00:31:07,397
In fact,
they varied the densities
721
00:31:07,499 --> 00:31:08,966
of the aggregate in the cement.
722
00:31:09,068 --> 00:31:11,168
They would use
high-density aggregate
723
00:31:11,270 --> 00:31:12,803
in the foundations
and in the walls,
724
00:31:12,905 --> 00:31:14,471
but then, up in the dome
725
00:31:14,573 --> 00:31:16,240
where the cement had
to be a lot lighter,
726
00:31:16,342 --> 00:31:19,576
they would use
a lower-density aggregate.
727
00:31:19,678 --> 00:31:21,645
narrator:
It's this ingenious engineering
728
00:31:21,747 --> 00:31:24,348
that allowed the Romans
to build in concrete
729
00:31:24,450 --> 00:31:28,018
without the need
for reinforcement or pillars.
730
00:31:28,120 --> 00:31:33,023
- There's one very special
quality of Roman concrete.
731
00:31:33,125 --> 00:31:35,893
It continues to harden
with age.
732
00:31:35,995 --> 00:31:40,564
The dome of the Pantheon
is now stronger
733
00:31:40,666 --> 00:31:45,335
than it was 2,000 years ago.
734
00:31:45,437 --> 00:31:49,106
narrator: Modern concrete
buildings rarely last 50 years.
735
00:31:49,208 --> 00:31:51,675
They are in constant
need of repair.
736
00:31:51,777 --> 00:31:54,411
♪ ♪
737
00:31:54,513 --> 00:31:57,447
The Capitol dome
was finished in 1856
738
00:31:57,549 --> 00:32:00,984
and has had two extensive
restorations since then.
739
00:32:01,053 --> 00:32:02,552
The last time
the Pantheon dome
740
00:32:02,655 --> 00:32:05,555
was repaired was 202 AD,
741
00:32:05,658 --> 00:32:09,259
and that was after
an earthquake.
742
00:32:09,328 --> 00:32:11,094
And there was another
astonishing feature
743
00:32:11,196 --> 00:32:12,930
of Roman concrete.
744
00:32:13,032 --> 00:32:14,765
- Roman engineers were so ahead
745
00:32:14,867 --> 00:32:16,767
of their time
that they discovered that
746
00:32:16,869 --> 00:32:19,970
if they changed the chemical
composition of concrete,
747
00:32:20,072 --> 00:32:24,441
this would allow the concrete
to set even under water.
748
00:32:24,543 --> 00:32:29,012
narrator: Underwater concrete,
this was revolutionary.
749
00:32:29,114 --> 00:32:30,714
The key ingredient,
750
00:32:30,816 --> 00:32:34,651
a volcanic ash from the slopes
of Mt. Vesuvius.
751
00:32:34,753 --> 00:32:37,621
- It contained about 85%
volcanic ash,
752
00:32:37,723 --> 00:32:39,723
lime, water,
753
00:32:39,825 --> 00:32:41,792
and some even say
animal's blood.
754
00:32:41,894 --> 00:32:44,561
This stuff was strong.
755
00:32:44,663 --> 00:32:47,331
narrator: It doesn't let water
in like modern concrete.
756
00:32:47,433 --> 00:32:50,233
It's weather-proof,
and resistant to decay,
757
00:32:50,336 --> 00:32:52,502
and incredibly,
it meant that the Romans
758
00:32:52,604 --> 00:32:55,839
could build in the sea
and construct harbors.
759
00:32:55,941 --> 00:32:57,507
- They could
build artificial harbors
760
00:32:57,609 --> 00:32:59,309
wherever they wanted.
761
00:32:59,411 --> 00:33:03,747
The Roman Empire flourished.
762
00:33:03,849 --> 00:33:06,416
narrator: The Romans poured
the concrete into wooden
crates,
763
00:33:06,518 --> 00:33:08,118
which then sank into place,
764
00:33:08,220 --> 00:33:11,455
and the concrete
set on the sea bed.
765
00:33:11,557 --> 00:33:13,357
They did this again and again,
766
00:33:13,459 --> 00:33:15,158
building up the harbor,
767
00:33:15,260 --> 00:33:18,795
the concrete continuing
to harden over time underwater.
768
00:33:18,897 --> 00:33:21,465
♪ ♪
769
00:33:21,533 --> 00:33:23,533
The biggest concrete harbor
the Romans built
770
00:33:23,635 --> 00:33:26,136
was at Caesarea
in modern-day Israel.
771
00:33:26,238 --> 00:33:27,270
♪ ♪
772
00:33:27,373 --> 00:33:29,172
They shipped in 44 ships,
773
00:33:29,274 --> 00:33:32,309
each containing 400 tons
of volcanic ash.
774
00:33:32,411 --> 00:33:35,679
♪ ♪
775
00:33:35,781 --> 00:33:38,448
With concrete, they built one
of the biggest harbors
776
00:33:38,550 --> 00:33:41,418
in the ancient world.
777
00:33:41,520 --> 00:33:45,255
narrator: Caesarea harbor
was 90,000 square yards.
778
00:33:45,357 --> 00:33:49,059
That's big enough to enclose
30 football fields.
779
00:33:49,161 --> 00:33:52,262
It could accommodate 300 ships.
780
00:33:52,364 --> 00:33:54,831
- They used over a million
cubic feet of concrete
781
00:33:54,933 --> 00:33:56,633
to build it,
782
00:33:56,735 --> 00:34:00,337
and this thing extended out
into the sea almost half a mile.
783
00:34:00,439 --> 00:34:01,805
It was massive.
784
00:34:01,907 --> 00:34:04,441
♪ ♪
785
00:34:04,543 --> 00:34:07,010
narrator: Concrete was
an engineering breakthrough,
786
00:34:07,112 --> 00:34:09,346
and it has literally
shaped our world
787
00:34:09,448 --> 00:34:12,249
more than any other
ancient invention so far.
788
00:34:12,351 --> 00:34:14,918
♪ ♪
789
00:34:15,020 --> 00:34:18,155
We've seen the most incredible
structures and discoveries,
790
00:34:18,257 --> 00:34:21,291
but there can only be
one number one,
791
00:34:21,393 --> 00:34:24,461
the greatest feat of Roman
engineering of all.
792
00:34:24,563 --> 00:34:27,364
Quite simply, it was the
biggest construction project
793
00:34:27,466 --> 00:34:29,766
the Roman Empire ever undertook
794
00:34:29,868 --> 00:34:31,635
and it was unsurpassed,
795
00:34:31,737 --> 00:34:34,971
not for hundreds of years,
but for millennia.
796
00:34:35,074 --> 00:34:37,374
The greatest Roman engineering
breakthrough
797
00:34:37,476 --> 00:34:39,876
is next on "Ancient Top Ten."
798
00:34:39,978 --> 00:34:43,480
♪ ♪
799
00:34:45,784 --> 00:34:47,284
narrator:
It's Rome's Greatest Hits,
800
00:34:47,386 --> 00:34:49,119
"Ancient Top Ten's" list
801
00:34:49,221 --> 00:34:52,089
of the most amazing
feats of Roman engineering.
802
00:34:52,191 --> 00:34:53,457
[dramatic music]
803
00:34:53,559 --> 00:34:54,925
At number ten,
804
00:34:55,027 --> 00:34:58,428
we saw Caesar's
incredible bridge,
805
00:34:58,530 --> 00:35:01,731
and number nine was the deadly
repeating ballista.
806
00:35:01,834 --> 00:35:03,333
♪ ♪
807
00:35:03,435 --> 00:35:05,836
At number eight,
the underground cathedral,
808
00:35:05,938 --> 00:35:08,171
the Basilica Cistern,
809
00:35:08,273 --> 00:35:12,175
and number seven,
the extraordinary Nemi Tunnel.
810
00:35:12,277 --> 00:35:16,813
Number six was the horrific
mine that was Rio Tinto.
811
00:35:16,915 --> 00:35:19,216
And then at number five,
Barbegal,
812
00:35:19,318 --> 00:35:21,218
ancient industry.
813
00:35:21,320 --> 00:35:25,055
Number four was the mighty
polyspastos crane.
814
00:35:25,157 --> 00:35:28,458
Number three,
the amazing road system,
815
00:35:28,560 --> 00:35:32,362
and number two,
the concrete revolution.
816
00:35:32,464 --> 00:35:34,397
But what has been picked
as the greatest
817
00:35:34,466 --> 00:35:36,399
engineering feat of them all?
818
00:35:36,502 --> 00:35:39,970
What changed the world
more than anything else?
819
00:35:40,072 --> 00:35:42,839
It's the number one
Rome's Greatest Hit...
820
00:35:42,941 --> 00:35:47,410
♪ ♪
821
00:35:47,513 --> 00:35:49,746
Aqueducts.
822
00:35:49,848 --> 00:35:52,749
- Aqueducts were the arteries
of the Roman Empire,
823
00:35:52,851 --> 00:35:55,852
and the Romans
were master engineers
824
00:35:55,954 --> 00:35:58,355
at building them.
825
00:35:58,457 --> 00:36:02,025
narrator: Rome built
its first aqueduct in 312 BC.
826
00:36:02,127 --> 00:36:04,094
It was such a success
that they went on
827
00:36:04,196 --> 00:36:07,097
to build them far and wide.
828
00:36:07,199 --> 00:36:10,834
- A marvel of Roman engineering.
829
00:36:10,936 --> 00:36:12,536
Huge networks
830
00:36:12,638 --> 00:36:15,205
transporting gallons
upon gallons
831
00:36:15,307 --> 00:36:19,409
upon gallons of water
across the empire.
832
00:36:19,511 --> 00:36:20,844
narrator:
It's estimated that the Romans
833
00:36:20,946 --> 00:36:23,446
built 6,000 miles of aqueducts,
834
00:36:23,549 --> 00:36:25,048
which if laid end to end,
835
00:36:25,150 --> 00:36:27,284
would go 1/4 of the way
around the world.
836
00:36:27,386 --> 00:36:29,286
♪ ♪
837
00:36:29,388 --> 00:36:31,121
A ready supply of fresh water
838
00:36:31,223 --> 00:36:34,357
meant that Roman
civilization could flourish.
839
00:36:34,459 --> 00:36:39,029
Agriculture, industry,
and expansion of the empire.
840
00:36:39,131 --> 00:36:41,031
- They could establish
cities in places
841
00:36:41,133 --> 00:36:43,066
that they otherwise couldn't
842
00:36:43,135 --> 00:36:47,037
because they wouldn't have had a
secure supply of drinking water.
843
00:36:47,139 --> 00:36:48,738
narrator:
All across the empire,
844
00:36:48,840 --> 00:36:50,373
a supply of fresh water
845
00:36:50,475 --> 00:36:52,042
meant that cities
could grow and prosper.
846
00:36:52,144 --> 00:36:53,810
♪ ♪
847
00:36:53,912 --> 00:36:56,112
The main aqueduct
supplying the city of Rome
848
00:36:56,215 --> 00:36:59,649
was an incredible
57 miles long,
849
00:36:59,751 --> 00:37:02,752
but this wasn't
the only one.
850
00:37:02,854 --> 00:37:07,524
- Eleven aqueducts totaling
more than 300 miles in length.
851
00:37:07,593 --> 00:37:11,428
That's 183 Golden Gate Bridges.
852
00:37:11,530 --> 00:37:13,997
♪ ♪
853
00:37:14,099 --> 00:37:17,567
- In total,
over 300 million gallons
854
00:37:17,669 --> 00:37:19,903
of water flowed into Rome
each day.
855
00:37:20,005 --> 00:37:23,640
That's more per person
than modern day New York City.
856
00:37:23,742 --> 00:37:26,509
narrator: Enough for
drinking water, sanitation,
857
00:37:26,612 --> 00:37:28,311
bath houses,
858
00:37:28,413 --> 00:37:30,313
and even the occasional
spectacular event
859
00:37:30,415 --> 00:37:32,782
on an epic scale.
860
00:37:32,851 --> 00:37:34,618
- One of the most remarkable
engineering feats
861
00:37:34,720 --> 00:37:37,587
associated with the Colosseum
is for the inaugural games,
862
00:37:37,689 --> 00:37:39,889
they actually flooded
the arena floor
863
00:37:39,992 --> 00:37:41,358
for naval battles,
864
00:37:41,460 --> 00:37:42,792
and the next day
had it all drained out,
865
00:37:42,894 --> 00:37:44,728
and the stage back in place.
866
00:37:44,830 --> 00:37:47,430
narrator: Just as amazing
is the precision engineering
867
00:37:47,532 --> 00:37:49,432
that went into Roman aqueducts,
868
00:37:49,534 --> 00:37:51,935
and none more so than
the Pont du Gard
869
00:37:52,037 --> 00:37:53,770
in Southern France.
870
00:37:53,872 --> 00:37:55,672
- This thing is huge.
871
00:37:55,774 --> 00:37:57,274
16 stories high.
872
00:37:57,376 --> 00:37:58,775
164 feet.
873
00:37:58,877 --> 00:38:00,277
It's the height
of the Colosseum.
874
00:38:00,379 --> 00:38:01,978
Enormous.
875
00:38:02,047 --> 00:38:05,115
It's made of over
50,000 tons of stone,
876
00:38:05,217 --> 00:38:06,249
and it's still standing.
877
00:38:06,351 --> 00:38:09,352
♪ ♪
878
00:38:09,454 --> 00:38:11,087
- The bridge over
the gorge covers
879
00:38:11,189 --> 00:38:12,789
just a small section.
880
00:38:12,891 --> 00:38:17,260
The whole aqueduct actually
travels for 30 miles.
881
00:38:17,362 --> 00:38:20,630
Even today, that would be
a public works undertaking
882
00:38:20,732 --> 00:38:23,600
on an unimaginable scale.
883
00:38:23,702 --> 00:38:27,103
♪ ♪
884
00:38:27,205 --> 00:38:28,471
narrator:
The precision engineering
885
00:38:28,573 --> 00:38:30,173
that went into Roman aqueducts
886
00:38:30,275 --> 00:38:32,809
like Pont du Gard
is incredible.
887
00:38:32,911 --> 00:38:35,712
- The wow fact that stays
in my mind
888
00:38:35,814 --> 00:38:38,615
is that over the course
of the whole aqueduct,
889
00:38:38,717 --> 00:38:40,383
that's 30 miles,
890
00:38:40,485 --> 00:38:45,021
the drop in height
is only 55 feet.
891
00:38:45,123 --> 00:38:49,659
That is an absolute tour
de force of Roman engineering.
892
00:38:49,761 --> 00:38:52,495
narrator: The gradient
is less than 1%,
893
00:38:52,597 --> 00:38:55,465
imperceptible to the naked eye.
894
00:38:55,567 --> 00:38:58,702
- With a one-foot drop
every 3,000 feet,
895
00:38:58,804 --> 00:39:03,506
the rate of flow was
58 gallons per second.
896
00:39:03,608 --> 00:39:05,775
That's pretty amazing.
897
00:39:05,844 --> 00:39:07,177
narrator:
And there was yet another
898
00:39:07,279 --> 00:39:08,878
technological innovation
that was
899
00:39:08,980 --> 00:39:13,083
way ahead of its time,
the inverted siphon.
900
00:39:13,185 --> 00:39:15,418
As long as one side
is slightly lower,
901
00:39:15,520 --> 00:39:17,520
water flows from one pipe down,
902
00:39:17,622 --> 00:39:19,489
then up to the other.
903
00:39:19,591 --> 00:39:23,026
It meant that no valley
was too wide to cross.
904
00:39:23,128 --> 00:39:26,096
- The inverted siphon,
ingenious.
905
00:39:26,198 --> 00:39:27,931
Not only could water
be transported
906
00:39:28,033 --> 00:39:31,334
along level ground
and downhill,
907
00:39:31,436 --> 00:39:33,603
but thanks to
this innovation,
908
00:39:33,705 --> 00:39:36,606
they could transport
water uphill.
909
00:39:36,708 --> 00:39:39,275
narrator: When this principle
was applied to huge aqueducts,
910
00:39:39,378 --> 00:39:42,545
the Romans could transport
water no matter the terrain.
911
00:39:42,647 --> 00:39:44,848
There could even be
a series of these tanks
912
00:39:44,950 --> 00:39:46,783
from one valley
to the next.
913
00:39:46,885 --> 00:39:50,019
- The Romans perfected
the inverted siphon technique,
914
00:39:50,122 --> 00:39:53,189
and they rolled it out
across the entire Empire.
915
00:39:53,291 --> 00:39:54,724
In any one hour, they could
916
00:39:54,826 --> 00:39:57,293
make 10 million gallons
of water flow.
917
00:39:57,396 --> 00:40:01,030
Not just flow, it flowed uphill.
918
00:40:01,133 --> 00:40:03,366
narrator: An infrastructure
project on this scale
919
00:40:03,468 --> 00:40:06,136
had never been tried before.
920
00:40:06,238 --> 00:40:08,805
It hadn't even
been contemplated.
921
00:40:08,907 --> 00:40:10,707
- But that's what
the Romans were like.
922
00:40:10,809 --> 00:40:13,443
They'd come up with
the most amazing solutions
923
00:40:13,545 --> 00:40:16,546
no matter how crazy
or ambitious the plan.
924
00:40:16,648 --> 00:40:21,384
♪ ♪
925
00:40:21,486 --> 00:40:25,388
narrator: Aqueducts were the
veins of the Roman Empire.
926
00:40:25,490 --> 00:40:28,658
Their civilization
depended on them.
927
00:40:28,760 --> 00:40:32,228
The world hasn't seen
engineering on this scale
since.
928
00:40:32,330 --> 00:40:33,930
♪ ♪
929
00:40:34,032 --> 00:40:35,865
Roman engineering was
the greatest
930
00:40:35,934 --> 00:40:38,168
of the ancient world.
931
00:40:38,270 --> 00:40:40,603
It overcame
any obstacle in its way
932
00:40:40,705 --> 00:40:43,339
centuries ahead of its time.
933
00:40:43,442 --> 00:40:45,608
It transformed the Roman world,
934
00:40:45,710 --> 00:40:49,878
and in doing so,
it has transformed ours too.
78980
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