China’s Terracotta Warriors

Full Episode

The life-sized terracotta warriors of China are known throughout the world. This clay army of 8,000 including infantry, archers, generals and cavalry was discovered by archaeologists in 1974 after farmers digging a well near the Chinese city of Xian unearthed pieces of clay sculpted in human form.

An amazing archaeological find, the terracotta warriors date back more than two thousand years. But what was the purpose of this army of clay soldiers? Who ordered its construction? How were they created? Secrets of the Dead investigates the story behind China’s Terracotta Warriors and documents their return to former glory for the first time. The film premieres nationally Wednesday, May 4 at 8 p.m. on PBS (check local listings).

Transcript Print

Secrets of The Dead: China's Terracotta Warriors

Narrator:
More than 2000 years ago, the first emperor of China set out to build a lavish tomb where he could spend his eternal life.
The emperor needed fierce warriors to accompany him into the afterlife, to protect him from the unknown.
And so, to satisfy their leader’s wish, ancient Chinese craftsmen created an army of clay, 8,000 soldiers strong.
Now, 21st-century scientists are studying the terracotta warriors and making astonishing discoveries.

TITLES: CHINA’S GHOST ARMY

The year is 221 BC....
In Mexico, the city of Teotihaucan is expanding ... On track to become ancient America’s greatest metropolis.

In Egypt, the city of Alexandria boasts a 400-foot-tall lighthouse ... (one of the tallest buildings in the world, at the time).

... And in China, a team of craftsmen begins an incredible feat.

More than two thousand years later ... In 1974 ... Farmers digging a well near the Chinese city of Xian discovered strange fragments of clay sculpted in human form.

Intrigued, Chinese archaeologists carefully excavated the soil and made a staggering discovery.

8,000 clay warriors.... Infantry ... Archers... Generals ... Cavalry...

Buried in three pits

Near the tomb of one of history’s most powerful men.

The brilliant soldier and ruthless conqueror named Qin Shihuangdi.

More than two thousand years ago, he unified seven warring kingdoms into a single empire called China ... Giving himself the title of “first emperor...”

And he built himself an extraordinary tomb, one that dwarfed the ancient Egyptian pharaoh’s pyramids.

An ancient Chinese author recorded the splendors of that tomb ...

Its rivers and oceans made of mercury, its replicas of palaces, fully reproducing the emperor’s earthly realm.

But there was no mention of an underground army in this ancient text.

And nothing like it had ever been found, before or since.

The origins of the terra cotta warriors have remained a mystery for more than two millennia.

Now, archaeologists and scientists from around the world have joined together to find out everything they can about the statues—why they were made and perhaps more intriguingly, how they were made. Each soldier stands six feet tall and weighs more than 600 pounds.

Creating the terra cotta warriors was a stunning achievement.

They would have cost a fortune only an emperor could afford.

The task would have required years of work ... And endless ingenuity ... As workers struggled to make clay statues on a scale never attempted before.

And when they were finally finished, they were buried out of sight for eternity.

Qin Shihuangdi went to enormous trouble and expense to create these statues. Statues that would never be seen by human eyes after his death.

Just west of the first emperor’s tomb, archaelogist Jing Honwei is studying another royal tomb. One that might provide clues to understanding why the first emperor produced his army of clay.

In 537 BC…some three hundred years before the first emperor unified China ...

This gigantic pit was the tomb of Qin Jing Gong ... Ruler of the small kingdom of Qin ... And one of the first emperor’s ancestors.

These wooden boxes are grim reminders of what happened here on the day Qin was buried ... The ritual killing of his entire court.

Jing Hongwei (Translator):
When Qin Jing Gong passed away, he buried 186 living people with him.

... They were buried in these coffins. Each coffin was numbered, and each victim was also given a number. Every victim was buried in the coffin with his or her number. The position of every coffin had been preassigned.

Narrator:
Pride of place went to the ruler’s ministers and wives, assigned to the coffins nearest his own. Cruder caskets in the outer ranks held royal craftsmen, bodyguards, and other useful commoners.

They were all killed to serve their lord in death, as they had in life.

It is the largest human sacrifice ever found in an ancient Chinese tomb.

But there were others.

Jing Hongwei (Translator):
Almost every big tomb would have 100 to 200 corpses. This is a massive number.

Narrator:
Body counts like these from royal tombs conjure up images of mass slaughter.

But there’s no evidence of a violent massacre.

These bones belong to people buried in Qin Jing Gong’s tomb.

And according to archaeologist Zhang Zhongli, some of these people were happy ... Or at least willing ... To die.

Zhang Zhongli (Translator)
At that time, people believed that there was another world where people could carry on their lives after death ... Rulers’ attendants and followers were enjoying their lives with their masters when he was alive. So it was quite natural to follow him when he died ... For them, death was another form of life.

Jing Hongwei (Translator)
Some people were terrified and unwilling to die. But some other people thought their lives were meaningless without their master, so they wanted to follow their master to death, and considered this as a big honor.

Narrator:
Some committed suicide, others were murdered.

The answer to how they died lies in the bones.

Jing Hongwei (Translator)
This is a ... Human skull uncovered from a coffin in the tomb. We tested the chemical composition of the skull and hair and found that they both contained arsenic.

Narrator:
There are no traces of arsenic in the ground around the coffins ... which leaves only one possibility.

The arsenic must have been ingested by the victims – voluntarily or not.

Jing Hongwei (Translator)
Arsenic can be dissolved in alcohol. So we think that these victims drank arsenic wine and were poisoned to death.

Narrator:
When Qin Jing Gong took his ministers, servants and soldiers with him to the grave, he was following a thousand-year-old Chinese tradition.

Only 300 years later, the first emperor ... The most powerful ruler in China’s history ... Also buried officials, servants, entertainers ... And 8000 soldiers ... In his tomb.

But they were all made of clay.

What changed in those 300 years?

According to author Guo Xingwen, the ancient Chinese may have believed in human sacrifice... But that didn’t mean they liked it.

Guo Xingwen (Translator)
Today, we regard this as an inhumane thing. In ancient times, it was considered inhumane as well.

Most of the court officials weren’t willing to die. But they didn’t have any choice, since they would have been disloyal if they didn’t. The ritual system required them to die ... It would be their honor to follow the monarch, despite the fact that none of them would really like it.

Narrator:
But it was the violence of war that put an end to the practice of human sacrifice.

Less than sixty-five years after Qin Jing Qong’s funeral, China’s seven kingdoms plunged into war.

Known as the period of warring states, it lasted more than 250 years.

As generation after generation was wiped out, and populations declined by the thousands, sacrificing hundreds of people for the afterlife became an unaffordable luxury.

Guo xin-wen I/V (Translator)
At that time human life became more important ... As a consequence of years of war, the population had decreased significantly. Each state was struggling to maintain its population, since population means productivity.

Narrator:
By the time the first emperor ended centuries of war and unified China, human sacrifices were rare.

And rulers were substituting more humane ways of providing for their afterlives.

Zhang Zhongli (Translator)
Zhang Zhongli: In a tomb about three hundred years older than the first emperor, we found small pottery figurines some tens of centimeters high. This shows that pottery figurines were replacing living beings as burial objects.

From that point on, tombs which we found had more and more stuff of this kind.

Narrator:
But nothing on the scale of the terra cotta warriors.

The first emperor inherited the tradition of tiny tomb figurines ... but took it to new heights, literally.

His tomb figures were life-size ... And no two of them seem alike.

Their shoes ...

Their bodies ...

...And especially their faces ...

... All appear to be different.

Some believe the 8000 clay warriors are all individuals ... But no one has ever confirmed that.

Until now.

In Wellington, New Zealand, facial recognition expert Glen Cameron is about to use modern technology to analyze the ancient warriors.

He uses Neoface ... A facial recognition software ...

Glen Cameron
It’s been used throughout Asia and around the world in various forms. In border control, surveillance, immigration, and by the police.

We can match around 1 million faces per second.

So we’re very proud of it, and we think it’s gonna do a good job at today’s mission.

Narrator:
The software analyzes the faces of about 100 terra cotta warriors ... Instantly comparing eyes, noses, mouths and other significant features ... to determine if any match.

Glen Cameron
Let’s have a quick look at these top matches here. These two with the big fatter chins. So here we have very similar chin lines with the big thick chin. Similar mouth position. Nose slightly different, but the eyes, eyebrows very different.
There is a huge range of faces here. Very individual, very individual. Whole head very different in shape.

Facial hair. Very different facial hair. A lot of difference in the eyes. This guy is looking quite sad. Look at the eyebrows on this one. Nearly frowning. Very entertaining facial features in the eyes, in the eyebrows. This one here quite a flat nose. And this one here more normal.

There is some similarity between the warriors like some chins, the mouth, the nose. But they are all very unique. I think this is incredibly exciting and I am astounded they could be produced this these sort of numbers and made so, so individual.

Narrator:
8,000 individuals ...

It is a mystery whether they were portaits of the emperor’s soldiers or products of the warrior-makers’ imaginations.

... But one thing is clear:

Creating 8,000 clay individuals made the job of producing the terra cotta warriors even more difficult.

Zhang Zhongli (Translator)
Human-size statues are definitely harder than small statues to make. Whoever came up with the idea might not have known how difficult making them was going to be.

Narrator:
On a day forever lost to history, the emperor gave his orders:

8,000 unique figures, and all to be ready on the unknown day when he died ...

All of them strong enough to survive an eternity underground ...

And all of them beautiful and realistic enough to please the imperial eye.

Each one, different from the next.

And the emperor demanded perfection.

Day one of terra cotta warrior production ... Around 221 BC.

Two men can shed light on what it must have been like to face the challenge of making life-sized soldiers out of clay.

Zhang Binruo ... And Han Ping Zhe ... Make terra cotta warriors for a living.

Their factories churn out thousands of terra cotta warrior replicas every year ...

It is a thriving business that sends warriors across the world, to people fascinated with the first emperor’s army of clay.

Mr Han (Translator)
Our Terra Cotta Warriors are exported to countries like the United State, Germany, Japan, United Kingdom, and France.

We manufacture around 50,000 small terra cotta warriors each year, and about 200 full-size figures.

Besides the traditional statues, we also modify some elements according to our clients’ needs

This warrior is playing golf. We made it for our client, the Yajian Golf Club. The golf club gives it to winners as a trophy.

Narrator:
After more than twenty-five years in the replica business, Zhang Binruo and Han Ping Zhe have faced the same difficulties the original warrior makers did.

Like their ancient predecessors, they’ve had to figure out warrior-making step by step, through trial and error.

And just like ancient times, the problem is one of scale.

Zhang Binruo (Translator)
We started to make 40cm, 50cm, and finally like this one, one half of human size, about 1 meter tall. Tourists wanted even bigger size, we went through many difficulties.

Narrator:
The first challenge was simply choosing the right material.

Bricks or a tomb figurine can be made out of just about any clay.

But a typical terra cotta warrior stands nearly 7 feet tall and weighs up to 650 pounds.

Using the right material can mean the difference between a fierce warrior and a pile of broken pottery.

The right clay must be dense and sticky enough to hold together as it loses water and dries out.

... But not so dense the inside of the statue cannot dry.

Today, as it was 2000 years ago, success depends on finding a clay that’s tough enough to make a life-sized warrior.

Zhang Binruo didn’t have to look far for the right clay that could stand up to the job. The site is near the emperor’s tomb and his warriors.

Zhang Binruo (Translator)
This is called red clay, it is sticky and strong. We searched many places and could not find anywhere else with this much red clay. But we find that this place has a lot.

Now we only use red clay from here to make terra cotta warriors. 2000 years ago, I think Terra Cotta Warriors were impossible to be made with other soil or clay.

Narrator:
For the first emperor’s craftsmen, finding the right clay would have solved the first big challenge of making a life-size warrior.

But it would not have solved an even bigger problem:

How to make thousands of them.

Quickly.

The first emperor died in 210 BC ... Only eleven years after he ordered his terra cotta army.

His craftsmen managed to finish 8,000 warriors in just 11 years, producing more than 700 per year.

Replica makers today, using modern technology, can only produce around 200 per year…

… not even a third of what the ancient sculptors produced.

One clue to how the craftsmen accomplished this impossible feat comes not from the statues themselves…

But from something they once held in their hands.

Yang Fuxi is a 10th-generation bowmaker ...

He makes replicas of ancient Chinese crossbows ... Like the ones once held by some terra cotta warriors.

Even today, the hardest part is casting the crossbow’s metal trigger ... A challenge that’s made Yan deeply respectful of the men who made those triggers 2000 years ago.

Yan Fuxing (Translator)
We found one trigger at one city, and another trigger at another city that is 2000 miles away. Parts of the trigger are exchangeable. In modern terms, these are standardized parts. I don’t know how they designed these parts.

Even now this is not an easy job, even experienced artisans need to work carefully.

Narrator:
Archaeologist Liu Zhangcheng is an expert on the weapons found with the terra cotta warriors.

Liu Zhangcheng (Translator)
We found more than 30,000 arrowheads in the pits.

We tested the arrowheads, and found the difference in their sizes to be less than 1cm; some of them only have a difference of 0.22mm. The difference is very tiny. We know that weapon manufacturing was standardized.

Narrator:
The first emperor’s weapon-makers signed their work ...

And so did his warrior-makers.

Archaeologist Yuan Zhong Yi has identified their names.

Mr Yuan (Translator)
In each of the figurines you can find the name of the craftsperson in the most hidden places. They did this in hope that people wouldn’t see their names.

Narrator:
Signing their work meant they weren’t anonymous.

But it seems they didn’t have a choice.

Mr Yuan (Translator)
This is to allow their managers and superiors to check their work.

If things are not constructed well, the worker may be asked to re-craft them or, in the worst case scenario, go to jail or be decapitated.

Narrator:
The warrior makers had two major advantages:

Their experience working on the imperial assembly lines producing bows…

And knowing that the likely alternative to success was death.

Both would no doubt have helped them solve the immense problem of making 8000 life-sized figures in just over 10 years.

After years of trial and error, modern replica makers have learned there’s only one way to mass-produce large clay statues quickly..

They must push the clay into a mold

Wait two or three hours for the clay to harden ...

Remove the mould and prop up the clay torso with wooden sticks ...while workers carve details ...

Make the heads, hands and legs in separate molds…

Let everything dry out for 10 days to 2 weeks ...

... And then fire all the pieces separately in the kiln.

The replica makers now know that if they make a whole statue, it will collapse under its own weight before it dries ... Or fill with hot air and explode in the kiln.

Han Ping Zhe (Translator)
Because we mass-produce, making hundreds or thousands copies of one statue, moulding is the only way.

And that’s not just his opinion.

Archaeologists agree that 2000 years ago, the first emperor’s craftsmen knew that moulding was the key to efficient mass production.

Liu Zhangcheng (Translator)
Mass production was the only way to explain the large numbers of arrowheads we found ... The difference between arrowheads is tiny. I think they used moulds, so they were able to produce massive amounts of arrowheads with tiny differences.

Narrator:
Case apparently closed.

It would appear the ancient warrior-makers may have met the mass-production challenge by using moulds ... Just like modern warrior-makers do.

There’s only one problem.

Nothing suggests the ancient craftsmen used molds.

Yuan Zhong Yi (Translator)
This ... Broken half body gives us very important information about how terra cotta warriors were made. We can see the internal traces of the clay layers here, which shows how the clay coiled up. The sign of how the clay coiled up and joined together is very clear. Here is one clay coil, here is another clay coil. One coil after another, until the clay layers were all joined up inside the body.

You see this layer, this layer, this layer and this layer ... Until it reaches this place, near the bottom, one by one ...

So, this is how a terra cotta warrior is made.

Narrator:
The ancient evidence leaves no doubt: the original terra cotta warriors weren’t stamped out of moulds.

Moulds did play a part ... In making hands, ears, and heads ...

But as incredible as it seems, the bodies of all 8000 terra cotta warriors were made individually, by hand ... And with techniques that were revolutionary for their time...

Zhang Zhongli (Translator)
The ancient craftsmen used a simple method; they pounded the clay until it became soft, and rolled the clay into strips. Then they coiled the clay strips upward, we call this method clay-coiling ...the first emperor’s craftsmen were the first people in China to make statues this way.

Narrator:
Coiling was a difficult way to make more than 700 statues a year.

Archaeologist Zhang Zhongli has decided to find out just how difficult the task was…

By making a terra cotta warrior the old fashioned way ...

With replica maker Han Ping Zhe and his master craftsmen.

Mr Han (Translator)
When we opened our business, we weren’t sure how to make a terra cotta warrior. I read about the traditional clay-coiling method. And we tried it. It took us a month to finish one statue.

Narrator:
The heart of the challenge: Make a figure that is nearly 6 feet tall…

But only half an inch thick... That won’t collapse under its own weight, a danger that grows greater as the coiling goes higher.

Supporting the figure with wooden sticks helps. But the only real solution is to stop and let the clay dry over and over again before making the statue taller.

They must find a delicate balance between waiting long enough for the clay to dry but not so long it dries out and cracks.

Mao Sanxue (Translator)
When I looked at the terra cotta warriors, I was amazed by the ancient people’s achievement. My statues collapsed 3 or 4 times when I first started.

Narrator:
Today, molding a warrior takes 10 days to two weeks ...

Coiling one can take as long as a month.

But there was a reason the first emperor’s craftsmen chose the more difficult method.

While molding may be the best way to make the same statue over and over again…

…the craftsmen weren’t making the same statue over and over. They were making 8,000 unique ones.

Zhang Zhongli (Translator)
If these statues were made with moulding, it would only be efficient if we made the same copy over and over again ... This was not the goal of the ancient people.

With the clay-coiling method, it is easier to make each terra cotta warrior different, whether it was fat or slim, tall or short ... The idea was to create a group of humans.

Narrator:
But if coiling made more sense for individualizing the warriors, it was still a slower process.

There was only one way to increase the number of statues produced. And the first emperor knew it.

Experts believe he made his terra cotta army the same way he built his gigantic tomb ...

With massive manpower.

Archaeologists have found 87 different names stamped on the terra cotta warriors ... So 87 master craftsmen must have been in charge of making them.

A team of apprentices would have worked under each master ...

Experts estimate 10 apprentices per team ...

Making at least 87 teams with nearly a thousand workers ...

Coiling one statue every month, each team could have finished 12 warriors every year ... And all 8,000 in only 8 years.

But today’s replica-makers know that having a huge labor force wouldn’t have solved yet another difficulty.

A problem that could have destroyed the production schedule... And their statues.

In northern China, winter temperatures plunge below freezing ... While in the summer, they soar into the 90s.

Both extreme cold and extreme heat will ruin clay statues before they can harden.

Zhang Binruo (Translator)
From long experience, I think the coiling method that was used 2000 years ago could not have been done at such temperatures.

Ideally the temperature needs to be maintained at around 20 degrees celsius.

Narrator:
Without the benefit of modern heating and cooling systems, the ancient warrior-makers faced a stark choice: find a way to keep their workshops at 68 degrees all year round... Or stop work for six months of the year.

No one knows for sure what they did.

But replica-maker Zhang Binruo has his own theory.

Cave houses ... Dug out of hillsides by farmers living near the first emperor’s tomb.

Warm in winter, cool in summer, they’re ideal places to live while tending crops.

Zhang believes that 2000 years ago, they were also ideal places to make terra cotta warriors.

Zhang Binruo (Translator)
In the summer, the temperature outside may reach 30 Celsius degrees; inside the cave house, it may be only 20-25 Celsius degrees. In the winter, outside may be-10 Celsius degrees, while the cave-house remains at 15-20 Celsius degrees.

They sculpted the terra cotta warriors in cave-houses, then fired the statues after sculpting by sealing the entry of the cave-house and turning it into a kiln, so they could fire the statues inside.

Narrator:
Today’s warrior makers’ struggles provide insight into the immense challenges facing the creators of the clay army.

Sculpting 8,000 warriors in just over a decade ... No two of them alike ... Without having done so before.

But evidence also shows there was far more to producing the statues than simply sculpting them.

To satisfy their emperor, the ancient warrior-makers had to meet one more challenge.

Today, experts are reconstructing the final work that finished the terra cotta warriors ...

What they’ve discovered has delighted some ... And stunned others.

After more than thirty-five years, experts have learned a great deal about restoring the terra cotta warriors.

But they’re still unable to prevent an archaeological tragedy.

The warriors emerge from the earth bearing traces of brilliant color...

But those colors vanish within a week ... Sometimes minutes ... After excavation.

Conservation expert Zhou Tie and his team race to save what they can, working on newly-excavated terra cotta warrior fragments... Fresh from the ground after more than 2000 years.

Zhou Tie (Translator)
When people created the terra cotta warriors 2000 years ago, all the pits were full of color ... When we excavated, the paints were almost gone ... Only small areas of paint remained, and those were in poor condition. The paint can easily fall off after excavation.

Narrator:
For years, an international alliance of experts from China and Germany has battled to save the terra cotta warriors’ colors.

It is a battle they still haven’t won ...

But at least they’ve identified the enemy.

A syrup-like substance with a pungent smell ...

That was one of ancient China’s most coveted treasures.

Lacquer.

According to German conservator Catharina Blaensdorf,

Every one of the 8,000 terra cotta warriors got a coating of lacquer from head to toe.

Catharina Blaensdorf
Lacquer is a very stable material and also in the antiquity they knew that it can survive centuries or even longer. ... So it had technical reasons, but also aesthetically reasons and reasons of meaning.

Narrator:
Lacquer was, and still remains, a valuable substance.

2,000 years ago, it was the ancient world’s plastic ... A hard resin that protects whatever it covers from decay.

And when it dries, its brown color transforms into a glossy sheen nothing else could equal.

Catharina Blaensdorf
Lacquer wares were luxury goods and they probably were so expensive that only the emperor could afford to lacquer a whole army.

Narrator:
For the ancient Chinese, its value was derived from more than just its strength and beauty.

It was also difficult to obtain.

The sap of the lacquer tree can’t be harvested until the tree is six years old.

And even then, only from June to September ... When the weather is warm.

Some experts believe it would have taken the sap of 25 trees to lacquer just one terra cotta warrior ... And as many as 200,000 trees to finish all of them.

That’s because lacquer harvesters can take only about 10 grams of sap from each tree ... Just enough to fill an egg cup.

Catharina Blaensdorf
You can't take very much because otherwise the tree will die. So you do it once, let it heal, and then continue.

Narrator:
The lacquer trees aren’t the only ones at risk.

Lacquer trees are related to poison ivy and poison sumac.

Touching the sap or even just breathing its fumes can cause extreme discomfort.

Catharina Blaensdorf
I tried to work with the lacquer several times just to experiments, and in the beginning not much happened, but then twice there was a strong reaction were really my hands and my whole face was covered with this rash

It's not painful. It's just itching and you have to um control yourself a lot not to scratch. [laughter] and it's not really looking nice.

And what normally happens is that you get this reaction several times and then there's an immunization, so afterwards you don't get it anymore.

Narrator:
Or so she thought. Breathing lacquer fumes during this interview triggered another reaction two days later.

The first emperor’s workers were forced to expose themselves to poisonous lacquer on a daily basis.

And 21st-century researchers must now work with the toxic sap so they can save the colors on the terracotta warriors.

Catharina Blaensdorf
The problem is that the lacquer layer was embedded in the wet soil for 2200 years,

Narrator:
As soon as excavation exposes the ancient lacquer to air, its moisture begins to evaporate ...

As the lacquer dries out, it begins to shrink…

Until it curls up and separates from the clay ... taking paint with it.

Catharina Blaensdorf
And finally the lacquer layers just flake off in tiny flakes and then there's no chance to bring them back to the terra cotta.

Narrator:
The only solution is to keep the lacquer moist so that it will stay attached to the terra cotta. Its water must be replaced by something that won’t evaporate.

One group of German scientists has tried coating warrior fragments with a plastic used to seal underground water pipes.

Then bombarding the plastic with electron beams from a particle accelerator ... Which evaporate water and bond the plastic to the lacquer.

But that can’t be done by archaeologists in the field ... Who may have only minutes to save a painted warrior.

Catharina Blaensdorf
We hope that we’ll find a method that is simple and cheap, easy to apply during the excavation and that helps preserve the lacquer layers in the first moment.

Narrator:
While saving the warriors’ color seems difficult, reconstructing what they originally looked like may be an even greater challenge.

The only clues are faded fragments of terra cotta ... Bits of paint found in soil ... And decades-old excavation reports.

But now, visitors to a Munich museum can see what the terra cotta warriors may have looked like.

After years of painstaking research, Catharina Blaensdorf and her colleagues have painted two warrior replicas as they believe they looked when they were finished more than 2000 years ago.

Catharina Blaensdorf
Many people were astonished or surprised because they didn’t expect them to be so colorful, and some people were also really shocked, because somehow they just liked the terra cotta version ... And they found it’s kind of disturbing and braking it up.

And they really asked me, they asked me, “are you really sure that it has to be like this?”... It’s based on our findings so we’re pretty sure that this is true, and they just have to get used to it ... And we tell them that of course we are not going to repaint the originals (laughs).

Narrator:
But there are even more complex mysteries surrounding the warriors.

When they analyzed surviving color fragments, conservation experts made an unexpected discovery.

One of those ancient colors differed from the others.

Known as Chinese purple, it has unique and surprising properties.

Halfway around the world, researchers at Stanford University are using the world’s most powerful x-ray machine to study those properties.

A team of scientists has focused a light one billion times brighter than the sun on a few flakes of Chinese purple...trying to find out exactly what they’re made of ...

Zhi Liu, Apurva Mehta, and Nobumichi Tamura are all physicists ... But they’ve set out to solve an archaeological mystery.

Zhi Liu
We’re looking at one clump of the Chinese purple pigment and the size is around 50 micron to 50 micron. So it’s about your, the cross section of your hair.

From a very tiny sample you can tell very big story.

Narrator:
Chinese purple is one of only two entirely man-made colors produced anywhere in the world before the birth of Jesus.

The other was Egyptian blue ... Created by chemists working for the pharoahs thousands of miles from China ... And centuries before the silk road opened up trade between China and the west.

Zhi Liu
People speculate there is a technology transfer from Egypt to china because of the similarity of those two materials ... Which is really significant in terms of technological development and the communication between two civilizations.

Narrator:
Stanford’s powerful x-ray machine confirms that Chinese purple and Egyptian blue shared all the same ingredients... With two exceptions.

Egyptian blue contains calcium ... While Chinese purple has barium in it.

And the Chinese also added something the Egyptians never used ... Lead oxide.

Nobumichi Tamura
It ... Indicates that the Chinese really actually invented the Chinese purple completely independently from the Egyptians there was no technology transfers at all.

Apurva Mehta
And that told us that the technology they used for forming this material was very unique.

Narrator:
If it wasn’t brought from Egypt, that means the Chinese created the pigment using their own methods.

The team believes those methods were not developed for art or science… but for religion.

This burial suit was made for a Chinese leader who went to his grave not long after the terra cotta warriors went to theirs.

A suit made of thousands of pieces of jade.

2,000 years ago, the Chinese elite believed jade would magically make them immortal ...

They paid alchemists to find a formula for making jade.

The alchemists created a jade lookalike called “Chinese glass,” made with barium and lead: The two key ingredients of Chinese purple.

As they searched for the secrets of immortality, did they also create Chinese purple?

Chinese glass and Chinese purple have nearly identical chemical compositions ... And their apparent connection doesn’t end there.

Around 250 AD ... Some five hundred years after the terra cotta warriors were made ... China’s religious beliefs began to change. People no longer buried themselves in jade to make their bodies immortal. Chinese glass disappeared.

And Chinese purple vanished at exactly the same time ... It was never made again.

It would seem Chinese purple has a sacred past. Fitting for warriors meant to accompany the emperor into the afterlife.

And across the United States, another powerful scientific tool has revealed that Chinese purple’s potential might lead to fantastic technological breakthroughs.

In Tallahassee, Florida, scientists have discovered that the terra cotta warriors’ purple paint is much more than just a beautiful color.

They made their discovery here… at the National High Magnetic Field Laboratory ...

Home of the 45t hybrid... the world’s most powerful magnet ...

It packs 45 teslas of magnetic force.

Facility director Eric Palm has a simple way of showing what 45 teslas can do.

Eric Palm
If I take this steel washer closer to the magnet you can see that it will be pulled, attracted to the magnet

I believe that the stored energy is about 20 sticks of dynamite
It’s dangerous enough that we don’t typically allow people that have not been trained to be around the magnet. We don't allow people to bring tours where they can see the magnet, just in case something bad happens.

Narrator:
Scientists from around the world, like Suchitra Sebastian of Cambridge University, use the magnet in their research.

Load just about any material on earth into this magnet’s core ...

And then pump in liquid helium to cool it down to hundreds of degrees below zero ...

The 45t hybrid’s power will force the material to reveal its hidden physical properties.

In 2006, Suchitra Sebastian and Neil Harrison put a few flakes of Chinese purple into the magnet’s core, and saw something astonishing.

Inside the magnet, the molecules of Chinese purple became a single magnetic wave, a unique state in the world of quantum physics.

The team dropped the temperature even further ...

And the magnetic wave lost its third dimension... separating into individual two-dimensional planes.

Neil Harrison
Well when I first saw this I was just in disbelief.

It was a big surprise, I mean it was a totally new type of discovery.

Narrator:
A discovery that might change the world.

Because studying shifts from three dimensions down to two could help make better superconductors ...

And better superconductors could mean more efficient magnetic trains ... Lower electricity bills ... And faster computers.

Suchitra Sebastian
It’s incredible to think that this material that’s been around for more than 2,000 years, that was initially discovered and in fact created by Chinese chemists and has been on this terracotta army for 2,0000 years. It’s incredible to think that we’ve re-visited this material, something that’s a fundamental advance in our understanding, in our 21th century knowledge of physics. And thats just mind blowing.

Narrator:
And there may still be other mysteries concealed within this ancient army.

More than 2,000 years ago, the terra cotta warriors were an emperor’s vision and a brilliant technological achievement ...

Today, scientists are revealing just how brilliant that achievement was.

And searching for other mysteries hidden within these ancient masterpieces.

END

Credits Print

NARRATED BY
LIEV SCHREIBER

WRITTEN AND PRODUCED BY
STEVEN R. TALLEY

EDITOR
GLEN MOLESWORTH

CAMERA
SCOTT PRESTON
BRIAN MCCLATCHY
PETE WINTER
MIKE ELWELL
CHRIS TERPSTRA

GRAPHICS
DONALD FERNS
DAVID BATSON
KARSTEN SCHNEIDER

ORIGINAL MUSIC
BRUNO BARRETT-GARNIER

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KATIE BROCKIE

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ED CAMPBELL

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ERROL SAMUELSON

ASSISTANT PRODUCER, CHINA
FELIX FENG

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SUZANNE LLOYD

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SERIES OPEN AND ADDITIONAL GRAPHICS

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A NATURAL HISTORY NEW ZEALAND LTD PRODUCTION FOR THIRTEEN IN ASSOCIATION WITH WNET.ORG AND NATIONAL GEOGRAPHIC CHANNEL.

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