Original subtitles

ALLAN: It'’s tiring, the winds blowing, its icy cold.

This is so steep I don'’t know how they got the bricks up here.

ALLAN [off-screen]: The Great Wall of China.

ALLAN: Wow!

It'’s like being on the top of the world.

Endless wall, endless watchtowers all the way to the horizon.

It'’s like nothing you could ever imagine.

ALLAN [off-screen]: It'’s been studied for decades, but now new technology

is revealing its secrets like never before.

I'’m Allan Maca.

An archaeologist and expert in ancient civilizations.

And I'’m going to investigate China'’s distant past

from a whole new perspective... space!

Today, state of the art satellites see the world in stunning detail,

and reveal hidden archaeology.

Enabling us to recreate a lost ancient world,

invisible to the naked eye.

Working alongside leading Chinese experts,

my team and I will travel to some of the country'’s

most remote and incredible landscapes,

and with cutting edge science, investigate previously unknown

cultures, lost cities and devastating cataclysms.

This is Ancient China as you'’ve never seen it before.

Just outside China'’s capital Beijing,

10 million people a year come to marvel at the Great Wall.

This is the biggest manmade structure on the planet.

But the only way to really see just how vast it is,

is from 500 miles above the earth.

Using satellite images, I'’m going to track the Great Wall

across towering mountains and remote desert.

Exploring massive defenses.

ALLAN: They would just start raining down fire and arrows from above.

ALLAN [off-screen]: Meeting archaeologists as they unearth its ancient past.

ALLAN: Wow this is amazing you'’ve literally just found these.

ALLAN [off-screen]: And revealing its long hidden secrets

SARAH: This looks really cool.

ALLAN [off-screen]: To discover if this great monument could be

even bigger and far older than we'’d ever thought before.

I'’m starting my mission 70 miles north of Beijing in the

rugged mountains of Jinshanling.

At a part of the wall that'’s remained unchanged

for hundreds of years.

You see pictures of the Great Wall in tourist books,

but this is something else.

Out here in Jinshanling, satellite data shows

how the wall crosses seemingly impossible peaks.

And every few hundred feet,

huge stone structures.

On the ground, these towers reveal meticulous engineering.

ALLAN: Look at how beautiful this is.

Really formal arches here, lots of space,

windows all the way around.

You have a 360 degree view over the landscape.

It'’s incredible.

ALLAN [off-screen]: This is just one of around 25,000 watchtowers

built by the Ming dynasty,

who ruled China from 1368 to 1644.

Between the towers, ingenious defenses.

I'’m seeing these strange holes along the wall

that open to the outside.

What they would have done is they would have taken about a

five-pound rock, hollowed it out,

stuffed it with gunpowder, put a wick in there and literally

just rolled it out the hole, and boom.

No more invaders.

ALLAN [off-screen]: The Ming went to these extraordinary lengths,

to combat a mortal enemy.

From space, satellites reveal vast grasslands to the north of the wall.

Wild enough today, in the days of the Ming,

this was home to tribes of nomadic horseman.

The Mongols.

These fearsome warriors had been attacking and pillaging

China for centuries.

The Ming built the Great Wall to keep them out.

Now, 600 years later,

Chinese experts are using science and technology to

reveal its secrets.

SARAH: Everywhere I look I see watchtowers on the top of the mountaintops.

ALLAN [off-screen]: Near a remote section of the wall.

SARAH [off-screen]: This view is unbelievable.

ALLAN [off-screen]: Canadian archaeologist Sarah Klassen is

on her way to meet one of the teams carrying out this

ground-breaking work.

Li Zhe and Professor Zhang from Tianjin University are

using drone data to create a 3D model of the entire

Ming dynasty wall.

It'’s the most complete scan ever attempted.

SARAH: Without this technology doing something like this

would not be possible just look at the landscape,

you'’d have to scale up all of those cliffs and map all of

these features it would take decades if it would even be

possible at all.

ALLAN [off-screen]: The new scans reveal the incredible achievements

of the Ming in some of China'’s most extreme terrain.

Even on completely impassable ridges,

they still succeeded in erecting towers.

SARAH [off-screen]: Can you show me what you'’ve done here?

ALLAN [off-screen]: And within the scans, new discoveries.

Li Zhe has spotted mysterious openings,

along the base of the wall.

Using his data, I'’m heading 120 miles east,

to investigate.

ALLAN: Look at this rugged landscape.

Check out this ridge, see the watchtowers up on the ridge,

that'’s where the wall is.

The wall is snaking all the way down to this saddle over

here, that'’s where I want to go...

ALLAN [off-screen]: Today, the wall here has crumbled away,

but originally it would'’ve stood as tall as a three-story house.

ALLAN: Oh, wow.

Can you imagine solid wall all the way down from this ridge,

then all of a sudden there'’s this door.

Clear through to daylight.

ALLAN [off-screen]: It'’s completely baffling, why would a defensive wall

have a doorway running right through it?

ALLAN: Yeah. This is a pretty small, compact space right now,

but without all this rubble here this would have been the size of a person,

they would have just walked right through here.

The crazy thing is, you know, this is not some random

hole in the wall.

This thing is incredibly well built.

Look at all these bricks, just a perfect,

beautifully made arch.

So this was planned and the question is why?

ALLAN [off-screen]: Li Zhe has found more than 50 of these doors

along this part of the wall.

And it'’s thought they could be used by scouts sent out

to spy on the enemy.

But the data are revealing something else.

The ragged edge revealed in this scan isn'’t a decayed doorway,

but the entrance to a hidden tunnel that was once bricked up,

before being smashed open.

SARAH: This looks really cool.

ALLAN [off-screen]: This new discovery is completely different from

any of the other openings Li Zhe has found.

Potentially a way of launching a sudden attack.

ALLAN [off-screen]: Smashing open this thin layer of

bricks, allowed the Ming forces to ambush the enemy.

Before Li Zhe'’s discovery, experts had no idea these

hidden tunnels even existed.

It'’s an incredible find.

ALLAN [off-screen]: The latest technology is revealing that

the wall is far more than a simple barrier.

It'’s a complex military system.

The big question is, just how far does it stretch?

Using satellite images, we can reconstruct how the Ming wall

extends far to the West.

From mountain ranges, through wild grasslands and into barren desert.

Right to its end, where the Ming stopped building.

Here, at the very furthest reaches of their empire.

A huge construction.

Far greater than any of the thousands of towers along the way.

What is it? And what was it for?

To find out, I'’m going to follow the wall to a far-flung

corner of western China.

♪ ♪

ALLAN [off-screen]: I'’m investigating the secrets of

one of the world'’s greatest ancient icons.

Using satellite data, I'’ve tracked the Great Wall all the

way from the mountains east of Beijing to the Gobi desert,

a 500,000 square mile expanse in the far northwest of China.

ALLAN: Just over here I can see sections of the wall.

The feat of engineering required to build something so

far out here, in just this barren desolate environment,

just kind of boggles the mind.

ALLAN [off-screen]: After hours following the wall,

something massive emerges from the desert haze.

A mighty fortress.

Today, the modern city of Jiayuguan is nearby,

but 600 years ago this fortress would have stood alone

in a desolate wilderness.

ALLAN: I never imagined I'’d ever see something like this,

all the way out here in western China.

ALLAN [off-screen]: The Great Wall terminates in the mountains

just a few miles south of here.

Making this incredible structure the wall'’s final gateway.

The last fortress at the furthest edge of the Ming Dynasty'’s vast empire.

ALLAN: Look at how massive this is.

This rivals any gate or battlement anywhere in the world at this time.

ALLAN [off-screen]: Here, you really get a sense of the ambition,

the engineering and the immense power of the Ming.

A deep moat, walls up to 36 feet high,

and watchtowers on every corner form three layers of defense.

And even if the enemy does make it inside;

there are traps designed to create devastating kill zones.

ALLAN: You walk into this courtyard and if you'’re an

invading army, they can close those doors,

close those iron doors there and you'’re trapped here,

and all of a sudden they would just start raining down

fire and arrows from above,

And your invading force is doomed.

This is an ingenious military strategy all set and fixed in

the design of this incredible fortress.

ALLAN [off-screen]: It'’s massive, but also meticulously built.

ALLAN: The precision of construction here is amazing

and the emperor demanded that and there'’s this legend that

says the architect told the emperor,

he said I can tell you the exact number of bricks it will

take to build this fortress.

He said it would be 99,999.

And incredibly, at the end of construction there was just

one brick left.

And that brick is set over there on that little ledge,

as a kind of mini monument to the incredible precision and

design of this fortress.

ALLAN [off-screen]: Its position, right at the end of the Ming Dynasty'’s Great Wall

earned it the name '’The First and Greatest Pass Under Heaven'’.

But this fortress is just one small part of a megastructure

like nothing else on Earth.

Just one end of their Great Wall of China.

♪ ♪

Until we had images from space, experts didn'’t know

how massive the Ming Dynasty'’s Great Wall really was.

But now, Chinese experts have calculated it'’s 5,500 miles long.

That'’s over 1500 miles more than previously thought and

long enough to stretch from New York to Los Angeles,

and all the way back again.

But new technology is also unearthing secrets,

that take us beyond the great empire of the Ming.

1200 miles away, Sarah has set up a base camp in

the shadow of the Great Wall.

We know the fortress of Jiayuguan marks the end of the

Ming Wall but the satellite data reveals something else.

SARAH: Oh wow.

ALLAN [off-screen]: Chinese experts have told Sarah about

another section, even further into the desert.

SARAH [off-screen]: If I zoom in on the satellite imagery

I can see that this part of the wall is much more eroded than

other parts of the wall.

So that might suggest that it'’s older than the parts of

the wall built during the Ming dynasty.

ALLAN [off-screen]: This wall stretches far beyond the Ming fortress

continuing west for hundreds of miles.

SARAH: The wall is completely straight in the middle of this desert.

There is absolutely nothing else around here.

I can'’t imagine why they would need to build a wall here.

ALLAN [off-screen]: So what'’s going on?

I'’m heading west in search of answers.

I want to know, just how old is this wall?

Where does it go?

And if the Ming didn'’t build it, who did?

ALLAN [off-screen]: I'’m now more than 230 miles west of

the fortress of Jiayuguan.

ALLAN: I'’m here in the Kumtag Desert and it'’s one of the

harshest environments I'’ve ever been in in my life.

You know, very little grows here,

the temperatures are literally below freezing.

It'’s a hell of a place to imagine finding archaeology.

ALLAN [off-screen]: Sarah'’s guiding me to faint traces of

what looks like an even older wall,

that she'’s spotted on the satellite data.

ALLAN: If I get up here, I think I can get my first glimpse.

Wow, this is cool and it'’s not exactly what I expected.

Man, it looks kind of primitive.

I wanna see more, I wanna get up closer.

ALLAN [off-screen]: Here in the middle of nowhere,

a stretch of ancient wall.

And it looks very different from anything I'’ve seen so far.

This is a very distinctive kind of material.

We have rammed earth packed down,

with a reed foundation.

These are reeds!

This is actually, you know, a type of thick grass,

pressed in there to serve as a foundation to hold the wall stable.

ALLAN [off-screen]: This framework is an ingenious way of building

even with the desert'’s loose sand and gravel.

But if the Ming didn'’t build this, then who did?

To find out, I'’m meeting Zhang Junmin,

the head of a team from the Gansu Institute of Relics and Archaeology,

who are digging for answers.

ALLAN: This is so cool, tell me what you have here.

ZHANG: These are two arrowheads we found nearby.

One is bronze and one is iron.

You can see that it'’s still sharp.

ALLAN: I'’ve never seen this shape to an arrowhead before,

you know where it'’s basically three-sided like this.

Is that common?

ZHANG: We found lots of these along the wall in this area.

These arrowheads are very typical of the Han dynasty.

ALLAN [off-screen]: 1500 years before the Ming.

Before the Roman Empire formed in the West.

And Cleopatra ruled Ancient Egypt.

The Han Dynasty rose to power.

They oversaw a golden age of art,

culture and economic prosperity.

ALLAN: They'’re so well preserved, I'’m just amazed.

Look at that edge.

It'’s just incredible.

The form is just so clear and beautiful.

ALLAN [off-screen]: These tiny arrowheads reveal something momentous,

that the wall here is more than 2000 years old.

It'’s an even earlier Great Wall of China,

that once stretched for over 6000 miles.

Much of the famous Ming dynasty wall was simply built

right on top, 1500 years later.

Battered by desert winds for over two millennia,

what remains of this ancient stretch of Great Wall,

are just fragments of what was once a mighty barrier.

ALLAN: It'’s kind of hard just looking at these ruined sections

of the wall to get a sense of what it looked like originally,

so using historical sources and archaeological evidence,

we'’ve made this pretty phenomenal digital reconstruction

of what the wall might have looked like.

It'’s just amazing. Whoa.

ALLAN [off-screen]: When it was first built,

the wall would have stood up to 20 feet high.

This thing was enormous.

I can only imagine being part of an invading nomad army and

coming up against this wall and thinking you know maybe

it'’s better to just go home, because this was formidable.

ALLAN [off-screen]: Then.

Another discovery, just unearthed from the desert

sands that suggests the wall was about more than just

defending Chinese territory.

ZHANG: We found this coin nearby.

It'’s a Wuzhu coin from the Han Dynasty.

ALLAN: Wow, this is amazing, you'’ve literally just found these.

ZHANG: It may be they were left here by merchants.

ALLAN [off-screen]: These merchants may have been traveling along

a series of ancient trade routes, known as the Silk Road.

Established by the Han, the Silk Road stretched from China

through central Asia and India,

to modern-day Turkey, Egypt, Arabia and Rome.

It brought huge wealth to China and had to be defended

at all costs.

So the Great Wall was not just about protecting the empire.

It also served to protect China'’s gateway to this vital

artery of global trade.

But there'’s something else intriguing here.

Alongside the wall, more ancient remains.

Rising from the desert, a mysterious, eroded structure.

My tech team, Ryan Kastner and Eric Lo, are joining me,

and working with experts from Peking University,

we'’re going to investigate.

ALLAN [off-screen]: I'’m on a quest to uncover the secrets

of the Great Wall of China.

And my tech team is working with researchers,

Ma Li, Wu Yunan and Ma Qinglong from Peking University

to investigate what seems to be a mysterious tower,

built near an ancient section of wall.

RYAN: So they'’re flying the drone now,

we'’re going to first do sort of a lawnmower pattern over

the top to get the aerial view of the tower there.

ALLAN [off-screen]: The drone takes hundreds of images of the structure,

which will combine to make a detailed three-dimensional model.

After that, the team will scan a four-mile section of the

wall for traces of any more remains.

RYAN: Using a drone to be able to fly will save us a lot of time.

A drone can go a lot faster than we can on foot.

ALLAN [off-screen]: Hours of flight, and 1500 individual pictures later.

RYAN: Hey guys, come on in.

ALLAN [off-screen]: And I'’ve come to check out the results

with archaeologist and leading Han Wall expert Yang Jun,

who'’ll help us interpret our findings.

ALLAN: Alright guys so show me what you got.

RYAN: Alright so, to give you some context,

you can see the wall from the satellite imagery very clearly.

If you look it'’s a nice linear feature here.

ALLAN [off-screen]: But switching to the 3D elevation model

reveals details not visible in the satellite imagery.

RYAN [off-screen]: So if we look actually in this spot here,

right where it bends there,

there seems to be a clear, clear bump there.

That doesn'’t seem to be natural.

You can see in the elevation model,

the redder it is, the taller it is.

And it'’s a five or six meter tall mound there.

It seems to make a whole lot of sense to us that that would

be another tower.

ALLAN: Yeah because it turns at an angle and cuts back south.

RYAN: Right exactly exactly, so that would be a natural spot

where you'’d want to look out to see on all sides where everything was.

ALLAN [off-screen]: The structure'’s height and strategic position

suggests it may have been a watchtower.

Then Ryan spots something totally unexpected.

RYAN: You can see a clear structure,

another tower that was behind the wall.

Basically on top of a hill.

ALLAN: This is really interesting.

Did they build towers off the wall?

YANG: From our research we'’ve found most of the towers

were along the wall, but there are a few that are outside it.

ALLAN [off-screen]: It'’s bizarre, some of these towers

are deep in enemy territory, miles beyond the wall.

Were they really just simple watchtowers?

Or could there be more going on here?

600 miles away, in a vault at the Gansu Jiandu Museum,

are ancient relics which could hold the answer.

JENNY: Ni hao. XIAO: Ni hao.

ALLAN [off-screen]: Research director, Xiao Congli has agreed to

show our historian, Dr Chai-Hui Jenny Liu, these amazing finds.

JENNY: These are wooden slips, they are about the length of a ruler.

The wood looks well preserved.

On it you have these writings in ink.

Very fine writing.

ALLAN [off-screen]: Buried in the desert for 2,000 years,

these slips were unearthed in what was once the office of

a military commander.

And they contain instructions for soldiers stationed at the towers.

JENNY: OK, they'’re really hard to make out.

Oh, first of all on the very top there is one dot,

and that tells you that'’s the beginning of the rules.

And the first two characters is Xiongnu?

Xiongnu. That means the Huns.

ALLAN [off-screen]: The Huns were feared nomadic horseman,

who roamed the Northern grasslands 1,000 years before the Mongols.

JENNY: So the rule here is talking about what you should

do when the Huns come into the border.

[speaking Mandarin]

JENNY: So the next characters say you must raise a flag on the pole...

[speaking Mandarin]

ALLAN [off-screen]: Raising this flag, a marker known as a Peng,

could only have one purpose, to signal other towers.

And there are even rules for what to do at night

when flags can'’t be seen.

JENNY: By night, start a fire on top of tower.

[speaking Mandarin]

JENNY: And do not put it out until the morning.

All towers that see this light should also light and it goes

all the way down the defense line until it reaches the

commandry where the soldiers are.

[speaking Mandarin]

ALLAN [off-screen]: And the slips even contain instructions

on how to signal how many enemies were attacking.

JENNY: So let'’s say you have more than 1,000 Huns and

that'’s what they'’ve sighted.

There is a very specific signal that they must send,

so that without words the commandry would know there are

1,000 rides coming toward us.

ALLAN [off-screen]: This tells us the towers we'’ve mapped in the desert,

including those deep in enemy territory,

are not simple watchtowers, they'’re beacon towers.

Part of a complex early warning system.

Using our drone data, we can now reconstruct a complete 3D

model of what they may have looked like.

Built over 2000 years ago,

they were made of rammed earth clad in plaster.

And stood up to 26 feet high, with platforms on top where

the fires were lit.

And thanks to the incredible insights revealed in the

wooden slips we now know that these towers formed a

sophisticated communication system,

designed to provide early warning of an attack,

and pass it for hundreds of miles along the wall.

What the Han created is remarkable,

but were they the first to build a defensive wall to

protect their empire?

To trace the wall back to its very roots,

I need to travel even further back in time.

To the reign of a tyrant of unrivaled power and ambition.

The man who conceived of another of ancient China'’s greatest icons.

The Terracotta Warriors.

ALLAN [off-screen]: I'’m in the city of Xi'’an.

Having travelled over 1,000 miles from the deserts of the far northwest.

This was once the Ancient capital of China.

I want to trace the origins of the Great Wall,

but to do that I need to go back in time to the formation of China itself.

And explore the story of China'’s first Emperor.

I'’m starting out with his most famous creation.

The Terracotta Warriors.

ALLAN: I'’ve been reading about this for years and years but

this is my first time here, and I'’m telling you nothing,

nothing prepares you for this experience.

This is literally one of the greatest achievements in all

of ancient civilization, anywhere in the world.

ALLAN [off-screen]: More than 6,000 figures.

Row upon row of soldiers and commanders.

An entire army immortalized in clay.

And all built for the first emperor of China,

Qin Shi Huang Di.

ALLAN: From where I'’m standing there'’s no two figures that are alike.

The uniforms are different;

their facial expressions are different, right down to the mustaches.

This tells me about the power that the emperor was able to

summon, in his lifetime as a ruler.

This is extraordinary.

ALLAN [off-screen]: From space, we can see that the huge hangar that

shelters the terracotta army is just one tiny part

of his massive mausoleum complex.

And at its center, is this.

Hidden within this strange-looking hill,

is the emperor'’s tomb.

It'’s never been opened.

Archaeologists don'’t yet know how to excavate it without

destroying the contents.

But I'’m meeting Doctor Zhang Weixing,

who has been using seismic scanning technology,

to glimpse what lies beneath.

ALLAN: What do you know about what'’s in there?

WEIXING: We know there'’s a huge burial chamber under the earth.

It'’s 160 meters by 140 meters in size,

and 30 meters deep.

And within that there'’s a huge nine-level platform.

ALLAN [off-screen]: Ancient texts say the tomb contains a

replica of the cosmos with pearls as stars,

rivers of liquid mercury, and even deadly booby traps.

It sounds far-fetched, but Professor Zhang has found evidence

that suggests there may be some truth to the legends.

WEIXING: We found some unusual things.

When we scanned we detected very high levels of mercury in the air,

so we know there is mercury inside the huge burial chamber.

ALLAN [off-screen]: Wow, holy smokes.

These findings suggest there'’s truth in the ancient texts.

And that means there may also be truth in what they record

of another of the emperor'’s construction projects.

A huge defensive wall.

The first Great Wall of China.

Though little remains today, the records show it stretched

for nearly 2000 miles across northern China.

They also reveal the human cost of the emperor'’s ambition.

ALLAN: He forced 300,000 soldiers and half a million

laborers to work on its construction.

And for many, it was a death sentence.

They died of starvation or fatigue,

or in some cases they were flogged to death.

But it cemented Emperor Qin Shi Huang Di'’s place in all of world history.

ALLAN [off-screen]: After an incredible journey spanning

thousands of miles and reaching far into the past,

I'’m nearing the end of my quest.

But one intriguing mystery remains.

Did the First Emperor really conjure up the idea for a

Great Wall, right out of thin air?

To find the answer, I need to go back even further,

to a time before his bloody rise to power...

and before the formation of China itself.

ALLAN [off-screen]: I want to investigate one final mystery

surrounding the Great Wall of China.

Just how did the First Emperor get his idea to build a

colossal defensive wall?

That question has taken me 300 miles north of Xi'’an,

to the Loess plateau.

I'’m following satellite images to mysterious lines of rocks

and steep earth banks, the remains of a primitive and

clearly ancient wall.

ALLAN: There'’s pieces of pottery, scattered all over here.

ALLAN [off-screen]: All around, clues to who built it.

ALLAN: I mean, this piece is just commoner.

Commoner, like cooking jar, and the designs on the outside

tell me this is very early.

We'’re talking about pre-Qin Empire.

ALLAN [off-screen]: 2200 years ago, at a time before the First Emperor came to power,

China was divided into seven warring states.

To protect their territories, each state built their own defensive walls.

Incredibly, these are the remains of a wall built before

the formation of China itself.

ALLAN: This is pretty cool.

ALLAN [off-screen]: In 221 BC, the king of one of the warring states,

Qin Shi Huang Di, is waging bloody war.

He crushes all other states, unites China and declares

himself The First Emperor.

With his newfound power, he combines the warring states'’ existing walls,

and builds new stretches,

to create one huge defensive shield,

over 3,000 miles long.

The first true Great Wall of China.

His incredible construction would be extended and

developed by the Han Dynasty.

And over 1,000 years later, the Ming dynasty would take

things even further, creating the monument we see today.

ALLAN: The Great Wall was not one single thing,

it was a mesh of many walls that span huge periods of time.

I mean, truly, China is defined by its walls.

ALLAN [off-screen]: My investigation has taken us

right across China, to the edge of Empire.

I'’ve tracked the Great Wall back to its very roots,

more than 2,200 years ago.

And revealed how it'’s not one wall but many,

that evolved over the centuries into an

astonishing military masterpiece.

We always knew it was big, but now,

using the latest satellite imagery and cutting-edge

technology, Chinese archaeologists are revealing

that this world icon is even greater than we ever imagined.

It'’s more than twice as long as previously thought,

spanning 13,000 miles.

Long enough to stretch half-way around the Earth.

ALLAN: On this journey I'’ve learned,

that the Great Wall was as alive and dynamic as the

generations of people who built it.

It'’s the result of struggle and achievement spanning more than 2000 years.

It'’s not just an enduring symbol of ancient China,

it'’s the story of China itself.

Captioned by Cotter Captioning Services.