NARRATOR: It's one of the greatest marvels of the ancient world.

China's Terracotta Army, 8,000 strong, fully armed and built for eternity.

Created more than 2,000 years ago, it was lost and only recently discovered.

Now this stunning treasure reveals the first empire to rule ancient China.

We found amazing archaeological objects.

ANDREW BEVAN: And the implications are enormous for archaeology.

It's going to be truly revolutionary.

NARRATOR: But who made this vast army?

How and why?

It's the creation of an amazingly advanced civilization.

MIKE LOADES: The Chinese crossbow is two millennia ahead of its time.

NARRATOR: Its ancient weapons excel in rigorous modern tests.

MARCOS MARTINON-TORRES: You cannot make a better arrowhead than this.

NARRATOR: Archaeologists piece together clues and try to decode these ancient wonders.

Warriors and weapons.

Chariots and horses.

An entire world buried for more than 2,000 years now sees the light of day.

Revealed in all its original glory, the "Emperor's Ghost Army."

Right now on NOVA.

♪ ♪ NARRATOR: It's been called the Eighth Wonder of the World.

A vast army of almost 8,000 warriors, all over 2,000 years old.

Larger than life-sized and made from terracotta or baked clay.

A stunning array of infantry... cavalry... and chariots.

Creating on such an epic scale must have been an extraordinary challenge.

How was it done?

And what can it tell us about ancient China?

Now a series of archaeological excavations shows the Terracotta Army is only the start, a small part of a vast complex estimated to be over 21 square miles.

On the outskirts, there's chilling evidence-- the mass graves of the people who built it, piled with bones.

The site contains hundreds of subterranean tombs, filled not only with the clay warriors, but also birds... horses... musicians... and acrobats.

All of this surrounds a huge man-made mound, the tomb of the man responsible for creating China's first empire.

So far, archaeologists have excavated about 1,900 terracotta figures, only a fraction of the number believed to be buried in three major pits.

Each figure is intricately detailed, weighs 300-400 pounds and is made from seven main parts.

The archaeological work has taken 40 years and much still remains to be uncovered.

JANICE LI: We found amazing archaeological objects.

So I think we cannot guess what's buried beneath in the whole tomb complex.

NARRATOR: But now archaeologists are finding new answers to many of their questions.

Why was the Terracotta Army created?

And how and when was it engineered?

Who were the people who built it?

And what was their fate?

Scientists have dated the charcoal found in the pits as well as the clay in the figures.

All the evidence indicates that the Terracotta Warriors were made around 2,200 years ago, more than 200 years before the birth of Christ.

It was the end of what historians call "the warring states period," when for over two centuries, China was devastated by rival states fighting for dominance.

Mass invasions and battles raged across the countryside.

But finally one of those states conquered all the others and created the Terracotta Army.

And all in a single lifetime.

The great mystery is how.

It's a mystery because the oldest surviving literary source was written nearly a century after the Terracotta Army was built, by the father of Chinese history, Sima Qian, who wrote these classic records of the warring states and later dynasties.

Surprisingly, he made no mention of the Terracotta Army.

Nor does any other source.

Over 2,000 years ago, these warriors were buried and forgotten.

No one knew they ever existed.

Then, one day in 1974, during a drought in Shaanxi province, Mr. Yang and other local farmers started digging a well.

He tells China historian Jonathan Clements what happened.

(translated): I used a pickaxe to dig the hole.

JONATHAN CLEMENTS: As they were digging down they found what they first thought to be the rim of a pot.

I said, "There's bronze under ground."

They also found bronze.

They found metal artifacts, so they start dragging cartful's of broken terracotta out of this well.

Then a shoulder and chest appeared.

CLEMENTS: As they dug away the earth around it, they realized that they were looking at the body of a statue.

They had the top of the armor and they saw an arm.

I told my friend, "This is a temple."

CLEMENTS: What if they have disturbed gods in an old temple?

That is bad news.

(Yang speaking Mandarin) CLEMENTS: Of course what he didn't know was the importance for the entire planet.

Because this is the most important archaeological finding in China of the last 100 years that you can look at and say ancient China was amazing.

NARRATOR: Archaeologists soon found heaps of broken terracotta-- bits of legs, headless humans and even horses.

All smashed after 22 centuries underground.

They were buried in three large pits.

Pit Two has only been partially excavated and still looks as it did when first unearthed.

The roof planks are thought to cover nearly 1,000 warriors and scores of chariots.

Pits One and Three have also been partially excavated and an elaborate restoration process begun, repairing hundreds of warriors and recovering their lances, arrowheads and swords.

(translated): It astounded the world when it was first discovered and is truly unique.

We have five ongoing archaeology sites in the mausoleum.

NARRATOR: The Terracotta Army Museum has become a major international tourist attraction, housing a vast treasure trove of ancient art, technology and information.

But can it be used to clarify how a 2,000-year-old culture overcame all the challenges of creating such an epic masterpiece?

It's a mystery that a joint team from University College London and the Terracotta Army Museum is investigating.

MARCOS MARTINON-TORRES: There are two types of visitors to the Terracotta Army.

Some appreciate the beauty in the detail.

You can choose any of these warriors and you will immediately admire the very personal facial expression, the individual hairstyle.

Other people are more taken by the sheer scale of this site, its magnitude.

How was it possible to orchestrate all the technological knowledge, all the resources and all the manpower needed and to do it so quickly?

NARRATOR: It was built in an amazingly short period, all within 37 years, the length of the reign of Qin Shi Huang, the first emperor of China.

That's according to Sima Qian's historical records, which state that he was enthroned in 246 B.C.

and that this is when work started on his mausoleum... ...and that 37 years later, he died and work stopped.

But by then Qin Shi Huang had built an empire.

His Qin state ended over two centuries of war and conquered all its powerful neighbors.

The first emperor now ruled many millions of people and an area that rivaled the size of the Roman Empire.

The Qin Empire gave its name to China, along with a legal system and one currency.

But the first emperor also had a reputation for extreme cruelty.

CLEMENTS: What we now call China is only called China because of the first emperor.

The problem the Chinese have today is reconciling this idea that he was a cruel tyrant and that hundreds of thousands of people suffered and died under his regime.

NARRATOR: His story in Sima Qian also lists some of his crimes as massacring prisoners of war, burning books and slaughtering his critics.

CLEMENTS: But also that he did some good.

He unified China.

He took these disparate states with different languages and with different writing systems, and he forced them all to be Chinese.

NARRATOR: Sima Qian's accuracy has been questioned, since he lived a century after the first emperor died and was a member of the succeeding dynasty.

But his account describes the emperor's obsession with immortality... which may help explain the motivation behind the building of his vast tomb.

LI: What he believed when he died, he still can carry on his life in the underground kingdom.

So he brought all of the things with him to the underground kingdom.

NARRATOR: The ancient Chinese saying "treat death like birth" meant he could enjoy his possessions in the afterlife.

This may have inspired the elaborate planning of his vast mausoleum and, overshadowing it all, the first emperor's own huge tomb mound.

The grand historian said the imperial coffin was buried under the mound, which was originally 350 feet high.

The mound has not yet been excavated for fear of damaging it, and it won't be until the contents can be safely preserved.

But Sima Qian vividly describes how a model of the empire surrounded the bronze coffin with miniature rivers of mercury flowing into seas and heavenly bodies on the ceiling above.

The tomb mound is the center of a mausoleum unrivaled in history, built so the emperor's afterlife matched his luxurious life before death.

Dams diverted streams around the tomb.

Over 300 coffins were filled with horse skeletons.

Other pits held models of exotic animals and even members of the emperor's court.

So we're finding musicians and acrobats and weight lifters.

So we're seeing an entire culture revealed to us.

NARRATOR: This is not just a mausoleum, but an eternal pleasure palace.

Two half-size chariots made up of over 3,400 parts.

Each is pulled by four bronze horses.

Their harnesses embellished with gold and silver.

LI: They got bronze chariot for his spirit to travel in the afterlife.

And also he got terracotta warriors with him to protect him in afterlife.

NARRATOR: Such beliefs may explain the creation of the Terracotta Army and why it is located a mile to the east of his tomb.

It stands guard between the emperor's grave and the states he subjugated to the east.

He may have feared that the spirits of his many victims would seek revenge in the afterlife.

So perhaps the terracotta bodyguards were created to combat any threat from the underworld.

The ongoing survey work has mapped the newest finds and shows the site is far larger than originally thought... covering the area of 10,000 football fields.

But how did the Qin craft so many imposing and intricately designed clay warriors?

Reassembling the broken figures is the first part of their restoration and reveals the clues to how they were made.

Each figure was hand-crafted from the local clay.

You can see on the broken figures how the torso was created by coiling clay around in layers to build the upper body.

LI: That's the marks here.

Probably the hand holding inside and then smooth outside.

NARRATOR: Master craftsman Mr. Han has studied the figures with the museum curators and worked to replicate ancient production methods.

So what's the weight of an average warrior?

(speaking Mandarin) LI: About 200 kilos.

That's over 400 pounds, wow.

Yes, so that's very heavy.

NARRATOR: Limbs, boots, hands and heads were all cast from the local clay, which was pressed into molds shaped for each body part.

Originally the legs were based upon molds used for drainpipes.

The molding process creates a variety of limbs that can be combined with the various torsos in different ways to create a mix of figures: archers, heavy infantry, cavalrymen, generals, officials and charioteers and even their horses.

Once the hollow mold is filled out with clay, it's joined and allowed to dry before the figure is assembled, ready for firing in a kiln or oven.

Mr. Han has built a replica of an ancient Qin kiln.

MARTINON-TORRES: So it's based on the real Qin archaeology.

LI: Yeah, that's based on the Qin, real Qin archaeology.

NARRATOR: The figures are sealed up and then fired for days to harden them.

The original figures are a combination of molded parts.

But are they clones or individuals?

There are a variety of different faces.

They are dark and light skinned... with varying facial hair.

They have many different eye shapes... and a dazzling array of hairstyles and headwear.

There are clearly differences among the figures, but is each one truly unique?

The scientists hope to provide a definitive answer, by making 3D models to allow precise comparisons.

Each figure will need to be scanned into the computer.

But 3D laser scanning is time-consuming and expensive.

So Janice Li is using a still camera as the first step in a process that will turn 2D pictures... into 3D models.

ANDREW BEVAN: This is a very new technique and the implications are enormous for archaeology.

And it's going to be truly revolutionary.

NARRATOR: Back in London, Andrew Bevan is compositing the photographs to create a 3D model.

BEVAN: What the software tries to do is to go through each photograph and define a set of features that it can recognize.

It might be, for example, the tip of an ear.

NARRATOR: In humans, no two ears are the same and Andrew Bevan wants to know if this is the case for the terracotta figures.

The computer maps the features in three-dimensional space, then joins them up to create the head.

BEVAN: We've done this particular warrior in all of his glory.

NARRATOR: These models are designed to allow precise comparison of everything from hands to heads, arms to armor or figure to figure.

Effectively, the sky's the limit.

In this particular case, I'm going to slice off the ear of the warrior so it could be compared to some others.

NARRATOR: This will show if they are all anatomically unique.

The results indicate that the ears vary in shape, with different sized earlobes.

What we've discovered so far through these 3D models is that no two ears are demonstrably the same.

These warriors seem to be very individual in the same way as a typical human population.

NARRATOR: Some archaeologists suggest that they are even portraits of real people.

So this was an army of individual warriors, each strikingly real and unique... the product of the skill, dedication and technique of the craftsman creating them.

Han's work really reflected the processes of making terracotta warriors 2,000 years ago.

(speaking Mandarin) Yes, so, it normally takes three days for Han to carve, you know, the details.

NARRATOR: Even today the individual style of the craftsman clearly shows up in his work.

MARTINON-TORRES: Mr. Han's ears.

LI: Yeah.

It's really big ear lobes there, yeah.

NARRATOR: But years of careful restoration, preservation and analysis have given rise to clues that the Terracotta Army was originally quite different from what we see today.

Flakes of bright pigments still cling to the surfaces of torsos, hands and heads, showing the warriors were once highly decorated and suggesting a colorful, even gaudy array when first created.

We can now see how the warriors may have looked over 2,200 years ago.

A dazzling display of colors, with painted figures and ornate chariots, all fully armed and intimidating.

But were they carrying sharpened war-grade weapons or merely symbolic representations?

After the wooden parts rotted away, all that was left on the floor are the bronze weapons once placed in the warriors' hands.

But how were these weapons made?

And how were they used?

To analyze them, Janice Li is creating silicon casts of the ancient weapons, using a technique originally developed for dentists.

LI: We use this silicon mold to get very clear impression on the surface.

NARRATOR: By putting the silicon impression under a scanning electron microscope, Janice Li avoids any damage to the original weapon and can examine the blades in extreme close-up.

The screen is filled by a tiny section of the blade.

The marks show it was originally sharp and still is today.

LI: These parallel fine marks show this really massive effort for sharpening these functional lethal weapons.

MARTINON-TORRES: So consistent.

You cannot do these by hand.

Every one of the 40,000 arrowheads was sharpened by somebody on a wheel.

NARRATOR: The identical parallel lines on so many weapons show this is mechanical sharpening on an industrial scale.

Only one type of machine could make these fine, even lines... a rotary lathe that uses a spinning stone to sharpen blades.

All the swords, all the lances, all the halberds, and every one of the 40, 000 arrowheads have been sharpened in the same way.

NARRATOR: Combat damages the edges of bronze weapons.

But the Terracotta Army ones are unmarked.

MARTINON-TORRES: There's no sign whatsoever of them having been used.

These are freshly made weapons delivered directly to the Terracotta Army.

I think it's obvious these are not representations for religious purposes.

These are real lethal weapons made to kill.

NARRATOR: This is the earliest evidence of rotary lathes being used for sharpening weapons on an industrial scale anywhere in the world.

They're really well done.

This is fantastic.

I think we are onto something exciting.

Yes.

NARRATOR: So the Terracotta Army was fully armed.

The heavy infantry carried the deadly "G" or halberd.

Some were over six feet long.

Military historian Mike Loades demonstrates how it was a highly flexible weapon and the Qin army's best defense against their greatest foe... cavalry.

A major threat to all Chinese armies of all states was cavalry... both horsemen and charioteers.

And the principal defense against them was the halberd.

Whoa.

Now obviously I had to stop the horse there or he would have impaled himself on the spear and that's really the first function of the halberd.

And you'll see it's got this cross piece, this transverse bar, so if I had gone hurtling into a line of halberds, this would have skewered the poor horse here, but it would have stopped, so the halberdier himself doesn't get trampled.

He can also use the spike to take out the horse's legs.

But what if the animal gets past the point of the halberds and I'm coming in with a lance?

He could use his halberd to lift the point so that it's done that and that's pushed it onto my throat and he has pushed me and where he can obviously be quickly dispatched.

NARRATOR: As well as the halberd, the Qin deployed a range of bronze weapons, including spears, lances and long swords.

But the ancient Chinese led the world in one particular branch of warfare: archery.

A variety of pre-Qin sources show the Chinese invented the crossbow centuries before the first emperor.

But how and why did it evolve to become the most effective offensive weapon of the age?

LOADES: The Chinese battlefield was full of arrow storms.

Storm after storm of arrows.

But that takes skill and training.

How could you do that with an army full of peasant conscripts that were there for a few months?

Well, the answer was in the Chinese crossbow.

Just a simple stock of wood easily mounts any bow, so the bow is already made.

It fits onto there and just with putting a cross piece in there you could lash that into position.

NARRATOR: None survive.

This is a working replica.

Its importance is shown by the ranks of terracotta archers, armed with crossbows and ready for battle.

But all that is left of the Qin crossbows after the wooden parts have rotted away are clusters of strange bronze objects found in the pits.

This is a bronze crossbow trigger, one of the most sophisticated three-dimensional engineering mechanisms of ancient times.

NARRATOR: They were mass-produced with all the parts made to fit together precisely as historians of the day recorded.

MARTINON-TORRES: The annals of Liu Wai who date to around the time of the first emperor, claim that if there's any misalignment in the parts of a trigger, it will not function.

NARRATOR: Using a replica, Mike Loades demonstrates the design of the trigger.

The real genius was the trigger.

The bronze, the cast bronze trigger, produced to a standardized form in their hundreds of thousands.

So it's got its very simple interchangeable component parts.

It comes apart very easily, and it goes together very easily, and this whole assembly just drops into a pre-carved slot in the bow, and you have got a bow ready to shoot.

NARRATOR: The trigger locks tightly and can securely hold-- and smoothly release-- the power of the bow.

LOADES: It is an ingenious bit of mass-produced, standardized military equipment.

NARRATOR: But any crossbow is only as deadly as its arrows.

Over 40,000 arrowheads have been excavated from the pits.

This is just one bundle of 100, a quiverful... discovered here in the middle of Pit One.

So what were these arrowheads made of?

A portable X-ray fluorescent spectrometer is used to explore the details of Qin metalworking.

This is today the simplest, fastest, even cheapest way we have of determining the chemical composition of something.

It's only recently that we are beginning to use it archaeology, bringing about a revolution in the way we can characterize materials.

NARRATOR: It shows the Terracotta Army's weapons are nearly all made from bronze, an alloy that's a mixture of copper, lead and tin.

At first the researchers assume that every part of the arrow will be a single blend of bronze.

MARTINON-TORRES: This is telling us the recipe that the weapon makers had for each of the parts of their weapons.

There's the head proper and then what we call the tang, which would be inserted in the longer bamboo shaft.

The tang contains 3% tin, 1% lead, and the rest is copper.

So it tells us that this is a bronze with relatively low amounts of lead and tin.

We can now turn it over.

We can immediately see a relatively high tin content that's around 20%.

This is an alloy that we know would be extremely hard.

NARRATOR: More tin makes for a harder, sharper arrowhead.

But less tin makes the tang more flexible and less likely to snap.

MARTINON-TORRES: When you only have bronze, you cannot make a better arrowhead than this.

This is as good as a bronze weapon is going to get.

NARRATOR: So they used two different alloys of bronze in one fused section of the weapon: the arrowhead and the tang, the part connecting the arrowhead to the shaft.

But how?

Master forger Andy Lacey is experimenting, trying to reproduce the casting techniques developed in China over 2,000 years ago.

You have your tang pre-cast, already exists.

You just insert it into the mold.

You can see that it sits within the space that's the arrowhead, and then... and put the top part on and clamp it together.

Then you see the tang just sticks out there and that's the funnel that would take the metal in.

It's got these two components beautifully together.

MARTINON-TORRES: Yeah, that's the important thing.

And it's welded on very tightly.

Very tightly.

NARRATOR: Joining the two bronze alloys reveals the Qin's impressive technical sophistication and innovative production skills.

But only a test can show if the replica arrowheads perform in practice.

Ancient Chinese sources give clues to how the bows that shot them were loaded.

We have some evidence that the Qin laid on their backs to span their bows.

That would suggest pretty powerful bows of about 200 pounds, which is more powerful than a hand bow is going to be.

NARRATOR: Mike's demonstration bow replicates the mechanism of an authentic Qin bow, but only creates a quarter of the force.

LOADES: And we're now shooting with more than four times the power.

NARRATOR: To test the replica arrows to the limit, he's using a modern bow with a 200-pound draw weight of the original Qin bows.

It's devastating against ballistic gel.

But how will it fare against Chinese armor?

This is the level of armor that an arrow has to defeat.

It's lamellar armor.

That means you've got scales, which overlap each other, and then behind that is soft textile armor.

And you can see on the Terracotta Warriors they're wearing quite bulky clothing, and armor is a composite defense of hard exterior with soft padding, and they've probably got felt coats under that.

Deep inside here is a piece of pork to represent the human being inside.

So that's the challenge an arrowhead has-- delivering that crucial thump to the target.

Safety off.

Well, it's stuck in.

It's done something.

By God and it's gone right through the pork.

That is a dead enemy.

It's actually gone right through and it's come out the other side-- through the pork, through three layers of hardened leather, through multiple layers of gathered silk, through a thick piece of felt, through a side of pork, and here it is out the other side.

NARRATOR: The Qin used the crossbow to powerful effect.

In 223 B.C., the Qin faced the vast Chu army on the banks of the Yangtze River.

The Qin tricked them and then attacked with their devastating archers.

This seemingly simple mechanism is two millennia ahead of its time.

NARRATOR: It would take over 1,500 years for European crossbows to surpass the Chinese ones in power, and only then with cumbersome levers and pulleys, making them far slower to use and difficult to master.

LOADES: You can learn to use this in less than two minutes, and it enabled a peasant army to be converted into state-of-the-art troops.

NARRATOR: The Qin army had become so well organized and equipped, it conquered all its rivals and ended two centuries of war.

The Qin leader now ruled all China as the first emperor.

The historian Sima Qian, writing a century later from the prospective of a succeeding dynasty, describes a frenzy of book burning.

JONATHAN CLEMENTS: All of the books in his kingdom were destroyed, possibly thousands of Chinese documents that we'll never get back.

A terrible cataclysm for Chinese history and for Chinese historians.

NARRATOR: It was, according to Sima Qian, a descent into complete tyranny as 700,000 workers were forced to expand the tomb complex.

On the far western edge of the site, chilling evidence has revealed the dark secret behind the making of the Terracotta Army.

Janice Li is heading into the orchards... (speaking Mandarin) Where mass graves have been excavated, filled with the bodies of workers, including women and children.

Worn down by the relentless toil.

Archaeologists also found leg and neck irons, while Sima Qian refers to some workers as convicts and men condemned to castration.

The all-controlling Qin bureaucracy gave each body an inscribed death certificate or dog tag.

Each is a moving testimony to an individual story of hard labor.

LI: Bu Geng Jiu is the builder's name.

(speaks Mandarin) means like he owed the government money.

So he needs to work here instead of paying off the money to the government.

NARRATOR: The story of worker Bu Geng Jiu is typical.

He was forced to work because he couldn't pay a crippling debt he owed the government.

It was this forced labor that enabled the Qin to create the Chinese empire.

Protected with the earliest stages of the Great Wall, connected with intercity highways and irrigated with networks of canals and locks.

Conscripted laborers and slaves also assisted skilled artisans in making the 8,000 Terracotta Warriors.

But how did the Qin do it all on such a vast scale and with such attention to detail?

The careful study of both the figures and the weapons now enables us to understand how the workforce was organized and controlled.

Inscriptions on the warriors reveal who made them.

They were built by groups, or cells, led by 92 master craftsmen, each probably controlling about ten workers.

These cells came from the palace factories or local workshops.

And the weapons also provide evidence of this highly productive and tightly controlled organization.

MARTINON-TORRES: We have hundreds, thousands of weapons here, but we want to find out how that was achieved.

How is it that they could produce so many weapons in such a relatively short period?

NARRATOR: To help answer this, Janice Li has meticulously plotted all the armaments found in Pit One.

LI: This is the map of all these bronze weapons discovered in the east part of Pit One.

So, like the red one showed the bronze triggers, crossbow triggers, discovered in the pit, and the black dots represent the arrow bounders.

NARRATOR: The plots are then compared with the analysis of the metal content of the arrowheads.

LI: This group really are very different from... MARTINON-TORRES: Yes.

NARRATOR: And the precise shape of the triggers.

This reveals that the triggers fall into distinctive groups, defined by their characteristic shapes.

For example, this hanging knife here is curved at this corner.

This other one here ends at an angle.

NARRATOR: The plots of the armaments in Pit One identified several distinct batches of triggers.

All the trigger combinations located in the top northeast corner are identical in size, bronze content and design, suggesting they were made by the same cell of workers, while this set of triggers is different, showing it was made by another cell of workers.

This is a series of cells working individually to create these metal weapon MARTINON-TORRES: All of this requires a very versatile workforce that can produce a sword today, a crossbow tomorrow, a halberd the day after, depending on what's needed as the work moves forward.

NARRATOR: The worker cells were trained to be not onlyroductive, but versatile.

I think this production model holds the key to understand how it was possible to produce something so colossal, so big, but also so sophisticated in a time window maximum 40 years, quite possibly less.

NARRATOR: Janice Li has also found crucial evidence about how the workers were organized by decoding inscriptions chiseled into their weapons.

They reveal a structure of strict supervision, where all the workers had to record their names.

MARTINON-TORRES: We can see individual workers working on different years of the reign of Qin; above them, the craftsmen, foremen that will be working with them; the officials; and then, on top of all, Lu Buwei, who was then the prime minister or the chancellor of Qin.

NARRATOR: The craftsmen at the bottom had to sign their names so any substandard work could easily be traced.

MARTINON-TORRES: Sometimes people referred to this supervisory system for quality control as a carrot-and-stick system.

If something was wrong with a particular weapon that didn't fit the standard, then one could identify worker Jing in particular and make him accountable for his error.

NARRATOR: Everything had to be perfect for an immortal army, created to defend the first emperor in his perpetual afterlife.

And perfection was achieved through fear.

Some recently discovered Qin legal codes detail a harsh system, where even minor crimes had terrible consequences.

CLEMENTS: The state of Qin didn't just define things like theft and murder as crimes.

Incompetence was also a crime, so not meeting a particular standard of workmanship would also have been met with savage punishment.

Maimings, you have tortures, you have executions.

NARRATOR: This was all part of the system the Qin had created to rule every aspect of life in the empire.

It was called legalism.

The grand historian Sima Qian describes a society organized into small groups, each person responsible for the others' behavior.

CLEMENTS: Every unit of five or ten houses was obliged to report on each other.

If anyone committed a crime within your cell and you didn't report it, the entire cell would be punished.

It's very likely that just as the army and society was divided up in this cellular way, that the artisans, the blacksmiths and the potters of the Qin world also worked on very similar lines.

It creates a vicious, brutal society of people informing on each other, and everyone was terrified.

NARRATOR: All the evidence shows that the Qin deployed small groups of skilled workers capable of mass-producing both weapons and individualized figures.

They were controlled by a rigid system of incentives and punishments.

In 210 B.C., 11 years after he conquered all his neighbors, the first emperor died.

Sima Qian records he was buried in a bronze coffin surrounded by rivers of mercury, laid out in a map of the empire.

His tomb mound has never been excavated.

But the Terracotta Army opened the door to a lost world.

This massive site stands as testimony to the ingenuity and ruthlessness of the ancient Qin civilization.

Its pioneering system of flexible manufacturing, combined with authoritarian rule, allowed it to create the eternal wonder of the Terracotta Army.

This remarkable discovery gives a glimpse into how one small state created a vast empire, perhaps foreshadowing the rise of a super power today: modern China.

Landslides: devastating killers.

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