All language subtitles for Ancient.Engineering.S02E07.1080p.AMZN.WEB-DL.DDP2.0.H264-chr00t_track3_[eng]

- [Narrator] The world's
greatest structures,

push the boundaries
of engineering,

all fueled by a constant
desire to innovate.

- Without engineering, there
would be no modern world.

- [Narrator] Gigantic buildings,

complex infrastructure
and ingenious inventions.

- Engineering is the key that
turns dreams into reality.

- [Narrator] Many of today's
incredible achievements

rely on breakthrough
technologies

first devised by
ancient engineers.

- It's astounding how
they achieved this.

- [Narrator] Early
civilizations built

on an unimaginable scale and
with incredible precision.

- They raised a
bar for engineering

in a way that no one
thought possible.

- [Narrator] These
are some of the finest

engineers in history.

- [Narrator] Redefining
the known laws of physics

and dreaming up the impossible.

They constructed
engineering wonders

from colossal stadiums

to mighty waterways

and complex machines.

All with the simplest of tools.

- You cannot imagine
the skills people

would've needed to
build like this.

- [Narrator] By
unearthing the mysteries

left by these ancient engineers,

we can now decode their secrets.

- That so many of their
creations still survive

is testament to their
engineering prowess.

- [Narrator] And ultimately
reveal how their genius

laid the foundations for
everything we build today.

(dramatic music)

From the very beginning,
in all of its endeavors,

humankind has been willing
to push the boundaries.

- Throughout the
history of humankind

we've always wanted to
go that step further,

higher, faster, deeper.

- [Narrator] The limits
of what can be achieved

are only bounded
by our imagination.

- Our ingenuity and our
innovation has allowed us

to build some of
the most extreme

engineering structures
in the world.

- [Narrator] And
extreme has meant

many things to many people.

- We might want to really
defend ourselves strongly.

We might want to
appeal to our gods,

but we might just build
for the sheer heck

of impressing people.

- [Narrator] Humans have created

the most extraordinary
feats of engineering

in the harshest
terrains on earth.

From shifting desert sands
to enormous sheets of ice.

But our desires to
go to the extremes

can simply be to
declare who we are.

- Sometimes we just
build in an extreme way

because we like,
as human beings,

to be the biggest and the best.

- This desire has been
driven by a need to impress

the next generation, to
make your mark on the Earth.

- [Narrator] Pushing the
boundaries of engineering

is not a modern phenomenon.

It goes as far back
as the ancient world.

At over 480 feet high and
constructed of an estimated

2.3 million blocks of stone,
the Great Pyramid of Giza

is one of the seven wonders
of the ancient world,

but in the neighboring
region of Mesopotamia,

another culture had
developed a structure

on just as monumental a scale.

In what is now Iraq,
Kuwait, Turkey and Syria,

between the great rivers of
the Euphrates and the Tigris

lay the productive
land of Mesopotamia.

Established by 5,000 BC.

It has become known as
the Cradle of Civilization

because of the sophisticated
cities which grew up here.

Some of them housing
over 50,000 people.

- The ancient peoples
of Mesopotamia

transformed the way
that we see the world.

There you'll find the
earliest evidence of writing.

They were mathematicians.
They measured time.

They were surveyors

and they transferred all of
those skills into engineering.

- [Narrator] The center of
their universe was the king

who wielded power
over his people

by claiming a unique
connection with their gods.

These deities decided their fate

on every aspect of their lives.

But how could the
king reach these gods?

- If you want to prove
to your population

that you are close to the god,

you are the god's
representative,

you want to go higher and
higher and higher still.

In that sense,

they were literally building
a stairway to heaven.

- [Narrator] The building
that would bring power

and prestige to the king,

was a multi-tiered
structure called a ziggurat,

meaning mountain peak.

And with some potentially
reaching seven stories high,

they may have been the
tallest manmade structures

on the planet at the time.

And the remains of these
gigantic engineering earthworks

are still visible to this day.

One of these is the Ziggurat
of Ur, built by one of the most

successful Mesopotamian
Royals, King Ur-Nammu,

to the god Nanna
in about 2100 BC.

- The Ziggurat of Ur, even
with its remaining tier

is still an impressive
feat of engineering.

It's something really
amazing to behold.

- [Narrator] But the
Mesopotamians had never seen,

let alone built, anything on
this colossal scale before.

Did they have the
brains and the brawn

to scale up their engineering?

- Up until this point,

they'd only ever built
humble, basic structures.

So to then take their building
to the monumental scale

of ziggurats, you
can only imagine

the challenges they
would've faced.

- [Narrator] The
massive Ziggurat of Ur

was one solid wall of bricks.

210 by 150 feet around the base.

And up to three tiers
with the base containing

as many as 720,000 bricks,
soaring heavenwards.

It featured three huge
staircases, one in the middle,

two others rising
perpendicular to it.

Two massive buttresses prevented
the weight of the building

thrusting the bricks outwards
and causing it to collapse.

And its thought a shrine at
the top was where the king

or priest made food
offerings to their God.

The main component
of their ziggurat

was something the
people of Mesopotamia

had developed and used
for thousands of years:

The humble mud brick.

- They made these bricks
from clay and reed in a cast.

Bricks were cheap because
they could be mass produced

using local materials.

So they were a
very effective way

of building these structures.

- [Narrator] The challenge
for these ancient engineers

was as monumental as
the ziggurat itself.

As a building gets taller,
the more important it becomes

to have solid foundations and
precision building techniques.

As it grows, so does
its self weight,

which all needs to be
supported in the lower levels.

A small error near the
bottom of the ziggurat

could lead to big
problems at the top.

But to date, the Mesopotamians

had only tackled
lower level dwellings.

- If you stack the bricks
one on top of each other

in a straight line,
you can only go so high

before you create an
unstable structure.

- [Narrator] The
Mesopotamian builders

had to think out of
the mud brick box

to come up with a new
method of arranging bricks.

- There are a number of things
that the engineers could do

to make the structure
last longer,

to make it stronger
or more rigid.

They could fire the bricks

to make the bricks
themselves stronger.

They could also lay the
bricks as we would do,

in overlapping courses so
that there is no single line

of weakness that runs
right through the building.

The bricks help
reinforce each other

and make the structure stronger.

- [Narrator] But there
was another risk factor.

Situated on a huge floodplain,

flash flooding could see
inches of rain falling

within hours, landing on
the flat mud brick tiers

of the ziggurat.

- Now remember if you have
an extreme weather event,

any building constructed
out of mud bricks

is gonna be in danger.

It could turn to
a pile of slush.

- [Narrator] To mitigate
water damage on the bricks,

the builders took
advantage of a material

that was in abundant supply
in this part of the world.

Bitumen, a petroleum
based substance

found in natural
lakes in the region.

- Bitumen is a tar-like deposit.

It's sticky, black,
very viscous, and
also water resistant.

So it can be used to help
glue the bricks together.

It gives them some
structural strength.

It also helps waterproof
the structure.

- [Narrator] But reducing
water penetration

wasn't only about using
cutting edge materials.

They engineered the entire
ziggurat to include holes

at specific intervals
between the bricks.

- The weeper holes that
you see in the building

are actually gaps in
between the bricks.

And they're there for a
very functional reason,

which is to allow water to
come out of these holes.

So with any building
materials around the wall

and on the inside of the wall,

if you get any water
pressure, hydrostatic pressure

building up there that
could break the wall

if these holes didn't allow
the release of that water.

- [Narrator] These mass
construction projects

engaged every part of society

and were a constant
reminder of the omnipresence

of their king and their god.

- When you think about something
as complex as a ziggurat,

they are deeply
impressive people.

And it's because they looked
at the world around them

in ways that had never
been done before.

- [Narrator] The
Mesopotamian engineers

had not only created the
most monumental structures

of this part of the
world at the time,

but done it by refining
the use of the brick,

a breakthrough in engineering

that would be used
for millennia to come.

Today, they remain a key
element in many types of modern

construction because of
their inherent durability,

strength and ease
of mass manufacture.

But a remarkable
building built in 2014

has turned the humble
brick on its head.

- It's a trick of the eye.

It's geometry is
completely astonishing.

It defies logic.

It seems to defy
even engineering.

And yet there it
is, in front of you.

- [Narrator] The Dr. Chau
Chak Wing Building in Sydney

was designed by famed
architect, Frank Gehry,

whose work includes the much
lauded Guggenheim in Bilbao

and the Walt Disney Concert
Hall in Los Angeles.

Many of his designs
feature complex geometry

and a fluidity of form,
but this structure

is one of his most
ambitious creations to date.

- This incredible squashed
brown paper bag building,

called that because it
looks exactly like that.

It's got crumples in it,
bits that protruded out,

all these amazing
geometrical shapes in there

that look like how
could you build that

out of a solid
material of brick?

- [Narrator] But
this whole structure

is made from 320,000 of them.

To achieve this
undulating shape,

Gehry threw out the rule
book and digitally designed

five different bricks with
grooves and unique shapes.

- To be able to work
with these bricks

that were asymmetric and had
different geometries in them

must have been so challenging.

It's something that no
standard brick layer could do.

- [Narrator] These
unconventional shapes

when placed together, create
dramatically curved surfaces,

with some bricks sloping
out from the wall

by up to 28 degrees.

Keeping them securely in place

presented a new
set of challenges.

- The entire shell of the
building was a steel frame

onto which they could
then connect the bricks

using a specifically designed

bolt and groove
brick tie system.

- [Narrator] A channel
known as a frog

extends down the
length of each brick.

The tie consisting of
a threaded metal rod

with an adjustable square
nut sits in this groove,

clamping it onto the brick,

securing the brick onto
a steel stud frame,

which is covered with metal
sheeting and a waterproof

membrane that follows
the contours of the wall.

The tie can then be
adjusted in and out

to match the curvature
of the undulating facade.

- Then you could
apply the mortar,

which meant that the
ultimate end result

is that you get these
beautiful geometric shapes.

This is really art
meets engineering.

- [Narrator] The Dr.
Chau Chak Wing Building

pushed the craft of
bricklaying to its limits

and enabled the
construction of a building

which makes a unique statement
in its urban surroundings.

But the ancients also challenged

the accepted wisdom of
construction techniques

when it came to
extreme structures.

For thousands of years,

humans have pushed
the boundaries

by engineering spaces
deep beneath our feet,

like the rock hewn churches
of Lalibela in Ethiopia,

carved in the 12th
century out of one piece

of volcanic rock, making
one of its 11 churches,

the largest monolithic place
of worship on the planet.

But the engineering ingenuity
required to create underground

earthworks like this goes
back to prehistoric times.

And one of the most
remarkable dates to 4,000 BC.

On the small island of Malta

is a network of underground
alcoves and burial chambers

called the Hal
Saflieni Hypogeum.

Believed to have been
engineered by neolithic farmers.

- They would've had a
very, very sophisticated

and complex understanding
of the world around them,

but unlike us,

they would've had access to
really quite primitive tools.

And that makes the
cutting of these catacombs

all the more ingenious.

- [Narrator] With
only basic implements,

they excavated a
sophisticated labyrinth

of subterranean chambers
completely by hand.

The Hypogeum's oldest
and uppermost level

consisted of a central space

and an entrance to
the lower levels.

The 13 to 20 foot deep
middle level of 15 chambers

included the popularly known
Oracle Room, an oblong chamber,

which created echoing
acoustic effects

and the third lowest level
at a depth of 33 feet

included five smaller
burial chambers.

In this society, the
dead and living coexisted

in the same sphere and the
caves would've been used

for ritualistic ceremonies
and burials year round.

- There wouldn't have
been the fear of death

in the same way as we
sometimes think of it today.

Death would've been
very, very present

in these prehistoric times.

And as a result, people
would've dealt with death

in a way that would've been
part of the daily cycle.

(somber music)

- [Narrator] It's estimated
up to 7,000 skeletons

could have been interred here

as part of their ritual burials.

But how could they carve
out such deep chambers

for their dead and
avoid cave-ins.

- In Malta there are regions
of what's called coralline,

which is very soft material.

Building into this soft material

would've made it unstable
and risk of caving in.

So part of the skill here was
finding the right kind of rock

to excavate and build into.

- [Narrator] But these
ancient engineers

knew their landscape well,

they chose an area of rock
made from ancient fossils

called globigerina limestone,
which carves easily,

but hardens on contact with air.

- The globigerina has this
extraordinary quality.

Once you've carved it,
there is a surface finish,

which gives it extra strength.

And therefore you can carve
with enormous precision

and with certainty that the
roof is not going to cave in.

- [Narrator] It's even
more astounding to consider

they built these
caves in darkness.

In recent times,
experts have shed light

on a secret that has laid
hidden for over 6,000 years

in the Oracle chamber.

- What they found was that if
you made a really low pitched,

almost like a sort
of chanting sound,

that that would resonate and
echo throughout the chamber.

So what you've got here
is some kind of primitive

sound system, creating
that transcendent vibe.

- [Narrator] These
ancient people

using the most rudimentary tools

had created caves of such
strength and complexity,

they still defy belief.

while ancient humans
moved heaven and earth

to build deep below ground,

in 37 BC, one man threw
everything at building

a monumental structure
in one of the highest,

most isolated places on Earth.

King Herod, known
as Herod the Great,

ruled the ancient Roman
province of Judea,

where Jesus would be born,

in the area now known as Israel.

This was a place of vast desert

flanked by the Dead
Sea to the east

and the Mediterranean
to the west.

But trouble was never far away.

- It was a real hotbed
of local strife.

So to the south you
had the Egyptians

and then all around you
had other Jewish kingdoms,

all competing for dominance

where Herod wanted
to base himself.

So therefore he needed
to build somewhere

which was incredibly secure.

- [Narrator] To keep his
enemies at bay, Herod turned

to a natural plateau that rose
1300 feet above the Dead Sea.

Measuring 1900 by 650
feet, it was called Masada.

- It's an astonishing place,

but very difficult
to climb up to.

If you could make
your way up there

and you could build
fortifications,

it would seem to be impregnable.

So for security, it's
a very good choice.

For practicality, maybe less so.

- [Narrator] Herod's
vision was an entirely

self-sufficient fortress
sustained by drinking water

which would be provided
from giant cisterns,

holding runoff rainwater, and
crops grown on the plateau.

He would have luxurious palaces

fit for a king of his stature.

And from this vantage point,

a bird's eye view
of his enemies.

Engineering a fortress
in such a remote location

would have its obstacles,

but Herod hit on
one stroke of luck.

- There was a ready
supply of dolomite rock,

which he was able to quarry
and to do the quarrying

he actually had the assistance
of some Roman soldiers.

It's worth remembering
every single Roman soldier

was a trained engineer as well.

- [Narrator] To move
the monumental stones

they had quarried
on the plateau,

the Romans had a range of
cranes in their arsenal,

including the greatest
heavyweight of them all,

the tread wheel.

It was effective
to lift huge stones

with the aid of another
Roman invention,

the chain Lewis key.

It works by applying
principles of the lever

and utilizing the weight
of the stone itself.

A wedge shaped hole was carved

out of the stone to be lifted.

Two curved iron lever
arms that swivel

were connected to a rope
and lowered into the hole.

A crane lifts the rope and
the weight of the stone

applies force to open the
arms which make contact

with the stone inside the hole.

This outward pressure creates
friction to prevent slipping,

allowing the stone to be lifted.

- With a Lewis key you
can lift the stone,

move the stone, place the
stone where you want it to go,

release the key
and the job's done.

Beautiful and simple.

- [Narrator] After six years,

Herod's city on a
hill was complete

with one of his palaces
even appearing to hang off

the cliff face on natural steps.

- This was a place of
gardens, of bathhouses,

of barracks and food stores.

This is an extreme
example of fine living.

- [Narrator] To top it off, he
erected the ultimate defense,

an almost one mile
reinforced perimeter wall,

with 27 watch towers.

- By creating a place with
resources for an army,

surrounded by a defensible
wall on top of an inhospitable

plateau, he must
have felt invincible.

- [Narrator] Dying in 4 BC,

Herod never had to
defend his fortress,

but within 77 years,
this siege-proof palace

would face one of the
most dramatic attacks

in the ancient world.

From 66 AD, the Romans were
engaged with putting down

a number of Jewish
uprisings across Judea.

Meanwhile, one group
of Jews took over

the small Roman garrison
stationed at Masada,

where they managed to
survive for several years.

- So the Romans have
decided they can't allow

this outpost of what they
would see as rebels to exist.

They've got to capture Masada.

- [Narrator] In 73 AD,
15,000 Roman soldiers

were sent to recapture it.

- The Romans arrive and
they see that the rebel Jews

have encamped themselves
in this tall plateau.

And so how are they gonna get
even close to taking it back?

- [Narrator] They decided
to build a giant ramp

from an existing outcrop
of rock to take soldiers

and their battering ram to
the front door of Masada.

Wooden boxes made
of stakes and braces

were filled with stones,
rubble, and soil.

They were stacked on
top of each other,

starting with a few
rising as the ramp

gradually increased
in height to 300 feet.

And as the ramp fell short
of the entrance to Masada,

they built foundations
of closely fitted stones,

75 foot square on top of the
ramp onto which they attached

a 90 foot iron tower from which
they could launch missiles.

- So you imagine you're one
of the Jewish defenders.

Now there they are at the
bottom of the cliff face.

Every day this ramp is
getting closer and closer

and there's absolutely
nothing you can do about it.

- [Narrator] But as
they reach the gates,

the Romans hadn't counted on
the reinforced battlements,

which the Jews had built to
resist the battering rams.

The Romans would
need another ploy.

- So they used catapults to fire

flaming bolts into
Masada itself.

And that started burning
a lot of the buildings

inside Masada, but the wind
was going the wrong way.

And therefore the flames
blew back towards the Romans.

So it looked as
though they may fail,

but then the fire
took hold in Masada.

- [Narrator] The whole
account of Masada

was recorded for posterity
by Flavius Josephus,

a Jewish historian
who lived at the time.

- Josephus says that
the Romans eventually

successfully overcame
the defenders

and they poured into the
citadel expecting to find

the 900 or so enemies they'd
been besieging up there.

- [Narrator] But what
greeted them was silence.

As they entered, they realized
the Jews were all dead.

- They found the Jewish
defenders had committed suicide.

- [Narrator] Josephus
gave an account

of what he believed occurred
amongst the Jewish people

before the Romans
entered Masada.

- The leader makes
this great speech,

inspiring them to
take their own lives.

And then they draw
lots so that 10

of them will dispatch the others

so that they don't have
the sin of suicide.

And then those 10
will kill each other

until there's a
last man standing.

They had this pact to avoid
falling into the hands

of their enemy because they
knew what the Romans would do

if they caught them alive.

- [Narrator] In 1963,
archeologists at Masada

made a remarkable discovery.

They unearthed stones with
names written on them,

which they believe
could be the lots

that were cast by the Jews.

Evidence which shows that while

one Roman feat of engineering
protected the Jews,

another ultimately
defeated them.

- We can say this was
an extremely impressive

siege operation by the Romans,
but ultimately a tragedy.

- [Narrator] Over the
centuries different cultures

have also built
death-defying structures

for defense, power or
just because they could.

In ancient China in 491 AD,

a group of monks found one
of the most unlikely places

on the planet to build
a place of worship.

- This is the most precarious
place to site a temple.

It looks crazy.

- [Narrator] The Hengshan
Mountains in north central China

rise over 6,000 feet.

One of the mountain ranges
considered sacred in China

for thousands of years.

The mountains were treacherous,

a place of snow and ice and
the occasional earthquake.

But this didn't deter the monks

from building a sanctuary
here for meditation.

- Building a temple in a
gorge that has been created

by floods running through
these two mountain sides

you'd think would be impossible.

However, these
ingenious engineers

used what they had
at their disposal

and built out of
the sheer rock face.

- [Narrator] At a dizzying 295
feet above the valley floor,

about 30 stories up
by today's standards,

the monks found their spot.

- This is not a building
for the faint hearted,

even to visit, let alone build.

- [Narrator] The
Hengshan Hanging Temples

would be a complex of
40 rooms and passages

dedicated to prayer and living

for Tao, Buddhist
and Confucius monks.

But how could they
affix a 10 ton temple

onto a sheer cliff face?

The first challenge was to get
themselves, their materials

and equipment up the
vertical mountain side.

- So if you are working
with heavy wooden poles

and then you need to haul
them onto the side of a cliff,

how do you do it?

- [Narrator] They decided
to do something more akin

to modern rock climbing
than ancient construction.

They would rappel
off the cliff face

to get to their building site.

Without a flat
foundation to work from,

they needed to engineer
a structure that
could be supported

from a sheer
vertical cliff face.

A secured rope at
the top of the cliff

allowed the monks to
abseil down to a point

horizontal to where
construction would begin.

A ledge was chiseled
out of a natural groove

in the rock face, and a
deep hole was cut into it

at the same level.

A fork was carved out of
one end of a wooden beam

and a wedge inserted
into the fork.

The pole was then pushed into
the hole in the rock face

and on reaching the end,

the fork created outward
pressure on the pole,

expanding it to secure
it tightly in place.

This protruding beam
acted as a cantilever

and was now stable enough
for the workers to stand on.

Wooden materials could
then be winched up

and this process was
repeated horizontally

along the cliff face.

A platform was erected
across the rows of poles.

So the structure could be built

and its entire weight
safely supported.

Hundreds of years
later, poles were added,

which seem to
support the temples,

but these are all for show.

Against the odds,
Hengshan has clung

to the sheer cliff
face for 1500 years

through the incredible
engineering skill

of Chinese monks hanging
hooks in the sky.

- You have a sneaking
feeling that these monks

might have needed
to be spiritual to
attempt this at all,.

'cause faith in God would
probably be a useful thing.

- [Narrator] There is no
greater challenge for engineers

than to build in evermore
extreme conditions

than a previous generation.

And nowhere is there
a better example

than in the national
park Zhangjiajie

where engineers in modern China
took a leaf out of the books

of the monks of Hengshan to
build the world's tallest

outdoor elevator
hanging from the cliffs.

- A huge pinnacle of rock.

How do you build an elevator
up something like that?

Not to mention the
accessibility of the site,

the Beilong Elevator
is in a national park.

It's in the middle of nowhere.

- It's a daunting task.

You've got the elements
to be aware of.

You're building out in the open,

let alone building
something like an elevator

where you've got to
safely transport people

from the bottom to the top.

This was daring engineering.

- [Narrator] The
Beilong Elevator,

standing at over 1000
feet is embedded directly

into the cliff face and
topped with a platform

which gives spectacular views
of the surrounding mountains.

- The first thing that you've
got to do is to make sure

that the materials
you are working with

can actually withstand
the immense pressures

that you're going to
be putting on them.

- [Narrator] Engineers
carefully chose

a very hard quartz
sandstone cliff face

as the site to build
the tunnels and shafts

they would need for
their structure.

- So you've got the bottom
part of the elevator

inside the rock face.

So that provides a nice
strong base for you.

But then the top of the elevator

is on the outside of
the mountain face.

So you've got this
exposed steel frame,

supporting the
lift as it goes up.

All these things that
you have to factor in

when you're designing
something that extreme.

- [Narrator] Secured
to the cliff face,

three lifts can carry
about 50 people at a time

with a total load of
up to 10,800 pounds.

But amongst the serene
beauty, danger lurks.

- It's built in an area
renowned for earthquakes,

it would be absolutely
terrifying if an earthquake hit,

this is a huge tall, narrow
mountain, and it's gonna wobble.

You're a thousand
feet up in the air.

You are crammed with
people into an elevator

and then there's an
earthquake coming.

What do you do?

- [Narrator] Engineers have
fitted the elevator cars

with monitors to measure
seismic activity,

which act as an
early warning system

so it can be evacuated quickly.

- That is an essential
piece of engineering.

- [Narrator] One of the fastest
exterior passenger elevators

on Earth, it travels up
to 15 feet per second.

- Would I ride in this lift?

As an engineer I'm intrigued.

If it's a brave day, I would.

- [Narrator] It's no
wonder it's called

the Hundred Dragons Elevator.

You can get a ride on a
structure as terrifying

as it's extreme, thanks
to one of the most daring

engineering solutions
on the planet today.

For the ancient engineers
back in the fourth century BC,

no location could have
been more ill suited

to sustaining a population
than where the city of Petra

sits today in what
is now Jordan.

- It's desert-like,
it's very, very hot

and very dry indeed
in the summer.

In the winter, it
can get pretty cold

and there's also flash flooding.

So it's an unstable and
hostile environment.

- [Narrator] But this area
had one thing in its favor.

It sat at an
important crossroads

supporting a trade taking
incense, myrrh, silks,

and spices from the East
to the West and back again.

- So this is an
important trade route

and the Nabataeans are
semi-nomadic people originally,

who participate in and help
control these trade networks.

- [Narrator] It's
this economic flow,

which provided a new
opportunity for the Nabataeans

to put down roots.

- The money is flowing
through the camel trains

and the trade routes,
but capturing that money

and organizing it
and using it to fund

the creation of a great city,

that's a real
engineering challenge.

- [Narrator] The innovative
engineering skills

required to establish the city

still amaze experts to this day.

Known as the Rose Red City,

famously hewn into
the pink sandstone,

Petra stretches across
100 square miles.

Climbing high up
sheer cliff faces,

it would've been home to
up to 30,000 inhabitants.

But none of this
would be possible

if they couldn't harness
one vital natural resource.

- What's the one
thing you need there

as this city begins to grow.

It's the need to store
and control water.

- [Narrator] Could the
Nabataeans turn an arid desert

using hydraulic technology

into one of the lushest
oases of the ancient world?

- Their only chance to survive
and thrive in the desert

was to harness the nearest
significant spring.

And this is the
spring at Ain Musa,

which is five miles
away on high ground

above where Petra is.

- [Narrator] The problem
was how to get it to Petra.

- You always have to
manage the flow rates,

the hydraulic
gradient of the water

so that it doesn't flow too
fast, doesn't flow too slow,

just nicely in the middle
zone, the Goldilocks zone.

So it perfectly supplies
your city with what you need.

- [Narrator] They came up
with one of the most complex

and audacious hydraulic
systems in the ancient world.

Tens of thousands of one
foot high fired ceramic pipes

were set at an angle sloping
at exactly four degrees,

allowing the water to flow
at just the right speed

from the spring to Petra.

But these ancient
masters of hydrology

had further ways to
optimize the flow.

Something which has
only been revealed to us

over 2000 years later.

Recent research on
shark skin has revealed

that it's rough texture
actually reduces drag,

enabling sharks to
swim at higher speed

than they would with
a smoother skin.

Inspired by this work,
researchers in industry

have found that just the
right sized indentations

could reduce drag on the
inside of gas pipelines,

the exterior of high speed
trains, even golf balls.

And archeologists
noticed something similar

hidden inside Petra's
ancient water pipes.

- Essentially that the
flow will be smoother

by five or 10% may
seem counterintuitive,

but the ridges seem
to help the water flow

smoothly along the pipe.

We don't know that the
Nabataeans would've
had any theory

about why this worked

like modern hydrological
engineers would,

but by trial and error, they
might well have found out

that pipes ridged in this way

produced a better flow of water.

- [Narrator] The water could
potentially flow faster

and further, reaching
more parts of the city.

As the population
increased, pipelines

and open canals sprung
up all over Petra,

but the unpredictable rainfall

threatened to cause
supply issues.

- Water is such a precious
commodity in the desert.

You have to be able to channel
water, store it in cisterns,

keep those cisterns
covered and cool

so the water doesn't all
evaporate or stagnate

and to be able to draw on it
in the summer when you need it.

- [Narrator] To better
regulate the water output,

cisterns with giant sluice
gates were built across the city

that could be lifted
or closed on demand.

- They were almost
like modern taps,

which you could turn off and on.

So if you have a caravan of
traders and merchants coming in,

you increase the water supply,
but then when they've gone,

you turn the tap off again.

It's water on demand.

- [Narrator] A massive
hydrology network

of 125 miles of pipeline
crisscrossed the city.

- They were going to palaces.

They were going
to private homes.

They were going to gardens.

It was a hydraulic
engineering paradise.

- [Narrator] Petra's
hydro-engineering was unmatched

for another 2000 years,

but eventually after seaports
became more important

and earthquakes
damaged the city,

it was abandoned to the
desert winds and lost in time.

With 95% of Petra
yet to be excavated,

who knows what other marvels
of engineering lie beneath.

But while the ancients harness

the natural water
resources of the mountains,

today's engineers
are using water

in a groundbreaking process,
deep beneath the Earth.

After New York became
an archdiocese in 1850,

the Archbishop of New York
decided its Irish Catholic

population needed
a large cathedral

to replace the old one
in lower Manhattan.

- New York in the middle
of the 19th century

was predominantly focused
on the southern part

of Manhattan Island.

So what is today
midtown Manhattan

was really quite a rural area.

- [Narrator] It was a project
that some considered folly.

- To build such a big cathedral
so far from the center

of New York life was a
very bold decision indeed.

- [Narrator] The
Archbishop's vision

was finally realized in 1879,

when the Gothic style St
Patrick's Cathedral was opened.

- This was America's
biggest Gothic cathedral,

and it would've towered
above all other buildings

at the point at
which it was built,

and for a community,
a Catholic community

that was coming to
America from Europe,

this was a beacon of hope.

- [Narrator] And
the gamble paid off.

- If you build it,
they will come.

And of course they did
because midtown Manhattan now

is where we have Central Park,

the Empire State
Building, Broadway.

- [Narrator] But
churches and cathedrals

can be notoriously
difficult to heat.

And in 2017 experts
decided the whole building

needed an improved
heating system,

but how could they update
the cathedral without causing

havoc to the precious
structure of the building?

- Changing any type
of historic building

is fraught with difficulty

because there is so much
protection around them,

but it's especially so
for places of worship.

- [Narrator] Engineers turned
to geothermal technology.

- Geothermal engineering is
essentially using heat energy

in the earth to do work for us.

So we can use use that to
thermally control buildings.

- [Narrator] This required
engineers to devise

a radical design solution to
access the geothermal energy

right beneath the cathedral.

10 wells each up
to 2,200 feet deep,

six times the height
of the spires,

were dug down to access
groundwater located in aquifers

beneath the bedrock that
remains at a stable temperature

of around 55 degrees Fahrenheit.

Two pipes connect each well
to the geothermal plant.

In summer, one pipe sends
this cooler groundwater

to a heat exchanger
inside the plant,

which creates chilled water
used to cool the air distributed

around the cathedral via
coil fans and air handlers.

This same water now having
absorbed the heat from the air

is sent back down
via a second pipe

where the heat is transferred
back into the bedrock.

In winter the reverse occurs
as heat stored in the bedrock

becomes the heat
source for the church.

This state of the art system

has saved up to 30%
in energy costs.

- It's genius really,
using geothermal energy

because if you're going to
heat stone above the ground,

why not take that heat from
the stone, the bedrock,

beneath the foundations
of the building.

- [Narrator] While
modern engineers

have found ways
to harness nature,

ancient engineers
sometimes had to vie

with the natural world.

And in ancient Sri Lanka,
one team of engineers

used material engineering
to overcome the challenges.

In sixth century India
when the Buddha died,

according to myth,
his ashes and relics

were deposited across the
ancient world in stupas,

temples built to
house his remains.

- This was to inspire awe.

It was to represent the grandeur

of the Buddha's spirit.

So these things,

they look like an entire
world unto themselves.

- [Narrator] Shaped in a dome

to represent the
burial mound of Buddha.

They rise from a wide base
curving to a tiny peak

at their zenith, with a cavity

which would be filled
with ancient reliquaries.

One of the most
impressive stupas

built from 273 AD
is Jetavanaramaya.

Soaring 400 feet high

with a footprint of 2.5
million square feet.

- This was the third biggest
structure in the world.

Second only to two of
the pyramids at Giza.

But what it's got
over those pyramids

is that they are built
of solid material.

This stupa is hollow.

And to do that is quite an
amazing engineering feat.

- [Narrator] Building a
structure on this scale

wouldn't be easy in the
jungles of Sri Lanka,

a place where
environmental forces

could destroy the very
fabric of the building.

- One of the big challenges
of building in the jungle

is that things
like to grow there.

It's very moist and it's a
constant warmth and sunshine.

So where the building meets
the earth, plants want to grow.

Now the roots and
the stems of plants

can destroy your
structure over time.

- [Narrator] Recent
research reveals

that it was these
ancient engineers
sophisticated knowledge

of the material world
which allowed them to build

a stable structure in
such extreme conditions.

- So what the builders of
the stupa did was ingenious.

They had elephants to
trample leaves down

that had been soaked in
arsenic and sesame oil.

And the arsenic was
essentially a weed killer.

So you're building
on solid ground

ones that won't be
undermined by plants.

- [Narrator] After filling
the 28 foot foundation trench

with bricks and soil,

they could start to
construct their dome.

Again, they turned
to material science

Experts have found the
bricks on the Jetavanaramaya

have a greater sand content
than our modern day bricks,

making them much stronger and
consequently able to tolerate

the vertical and horizontal
forces of a dome.

And they applied even
more material nous.

- By putting a slurry of fine
sieved sand and clay together

between the bricks, they had
this uniform glue between them

and they were clever
enough to roughen

one side of the bricks as
well so it had more purchase.

It gave the building more
structural integrity.

- [Narrator] A mega structure
that took 28 years to build,

requiring 93 million bricks,

Jetavanaramaya is the
tallest stupa ever built.

- When we look at the nature
of the materials they're using

and the way in which
they're using them,

these are up there with the
material scientists of today.

- [Narrator] These ancient
people used their most

cutting edge technologies
to overcome the challenges

of construction in
adverse conditions.

And today modern engineers are
still pushing the boundaries.

Now they're tackling
the final frontier.

One of the most extreme
environments in our universe.

- Lift off! We have a lift off!

- [Narrator] Space.

In 1998, a multinational group
of designers and engineers

conceived and built the
International Space Station.

Measuring 357 feet
from end to end

and hurtling through space
at 17,500 miles per hour,

it orbits the Earth so fast,

the crew witnesses 16 sunrises
and sunsets every day.

But housing a team of
astronauts safely in space

over long periods
of time presents a
plethora of challenges.

- How do you protect
your astronauts

from the bombardment
of radiation?

How do you provide them with
enough oxygen to breathe?

And how do you power a
space station sustainably

for years at a time.

- [Narrator] With an
electrical power system

connected by eight miles of
wire in a 446 ton structure,

where do you get your energy

without a power socket in sight?

- There's one thing that
you've got a lot of up there

that we sometimes don't
get enough of down here.

And that's the sun.

- [Narrator] Scientists and
engineers developed a way

to harness the space solar
power using solar arrays,

like our solar panels on Earth.

To launch them into space,
engineers folded the arrays up

and deployed them
remotely by signals

from the ground controllers
once they got into orbit.

Containing over
262,000 solar cells,

these giant arrays are rotated
on gimbals to face the sun

at the optimal angle
to generate far more

than the station
needs at any one time.

- It's almost inconceivable

that there's something
manmade up in space,

something that's helping
us understand the world,

the universe in which we live.

And it's all down to the
most brilliant engineering.

- [Narrator] Today
astronauts remain on board

for up to six months,

but in the future,
the length of stay

could dramatically increase
as humanity makes plans

to establish footholds
elsewhere in the solar system.

As a result of findings on the
International Space Station,

NASA's ambition is to set up
a permanent base for humans

to live on the moon
while private enterprise

dreams of establishing
not only travel to Mars,

but a permanent base.

Humans have spent
thousands of years

developing their
engineering skills

to build structures in
the depths of our planet,

at the extremes of temperature,

in the most challenging terrains

and have mostly succeeded
against the odds.

So when it comes to the
most extreme engineering

in the future, who's to
say the sky is the limit.

(dramatic music)