Original subtitles

- Some 45 kilometers from Mexico

lies the birthplace of the gods, Teotihuacan.

Erected in the 1st century AD,

it was as heavily populated as Athens.

Its 65-meter Pyramid of the Sun

is the second largest in the world

after the Great Pyramid of Giza,

built using only man's muscle power.

- All of Teotihuacan was created without any metal,

which is amazing because that includes everything

from the construction equipment.

So it wasn't the technology.

It was the people that created Teotihuacan.

- Of all Mesoamerican cities,

Teotihuacan is the most mysterious.

It was the stage of thousands of human sacrifices.

Its unique construction is the work of builders

who identity remains unknown.

- They were like Martians.

I mean, they pulled in people

into this highly organized city

on a grid system.

This was like nothing before.

- An enigma, the key of which

may lie deeply buried in 102-meter long tunnel

beneath the Pyramid of the Feathered Serpent.

- My theory

is that for a period of time,

the end of the tunnel was used to store the remains

of someone specific, someone with a lot of power,

most likely a first era leader of Teotihuacan.

- Archeologists have recently made

local discoveries that reveal the secrets

behind the construction of history's

very first pre-Columbian megalopolis.

Teotihuacan,

a city born out of an incredibly crazy idea,

to build the city as a giant cosmogram,

a perfect replica of the universe,

as a way to reach the level of the gods.

Following a perfectly orthogonal layout,

the city is divided into four quadrants,

separated by two avenues,

oriented by the four cardinal points.

At their intersection, the Temple of the Feathered Serpent

dedicated to the state god, Quetzalcoatl,

symbolizes the center of the universe.

At the north end of the two-kilometer long

Avenue of the Dead is the Pyramid of the Moon,

standing 42 meters high

and perfectly aligned with Cerro Gordo peak.

Facing west, the 215-meter wide Pyramid of the Sun

is only rivaled by the Great Pyramid of Giza in Egypt.

The surrounding lands feature 2,200 dwellings

spreading over 23 square kilometers,

a gigantic city that reached 200,000 inhabitants

in its heyday, and which took five centuries to complete.

- Teotihuacan was an impressive city,

one of the five largest cities in the whole world back then.

- It's really not just a city, it's a landscape.

It's so massive that the imprint of the ancient city

still is making thousands and millions of people

from all over the world come to visit it.

That's how successful they were

as far as creating a convincing template

that attracted that number of people.

- The city became a hotspot for worshipers,

thanks to its many lavish ceremonies,

much like on this night in 350 AD.

From the Avenue of the Dead, tens of thousands of pilgrims

marched toward the Pyramid of the Moon.

At its peak, and with their hands tied,

men awaited in fear.

Coming from all four corners of Central America,

they were diplomats, warriors, or merchants,

all well-born individuals whose sacrifice

was expected to please the gods

and consecrate the imposing monument.

With a swoop of the razor-sharp obsidian axe,

the men were beheaded.

They all suffered the same fate

and their corpses were placed

in the heart of the great pyramid.

- Every culture in the world

practiced sacrifices.

Even the Romans and the Greeks,

they all practiced human sacrifice,

but it was something very special here.

It was deeply rooted in daily life,

whether as self-sacrifice, collective,

or familial sacrifice, or even entire neighborhoods.

- You don't select just anyone for sacrifice.

They have to be specific individuals

selected for becoming the ultimate sacrificial victims,

representing the state that are able to fulfill

the function of a successful ritual dedication.

- For what reason?

Well, it was a way to guarantee

the durability of their landmarks.

And when they wanted to build a new monument,

they had to carry out a new sacrifice.

The more they gave, the more they expected to receive.

- While it is the most impressive,

Teotihuacan is also the most mysterious city of Mesoamerica.

Its civilization left no trace behind,

and its true name fell into complete oblivion.

It was only centuries after its fall that the Aztecs,

standing before such perfection, gave the city

the name of Teotihuacan, meaning birthplace of the gods.

One question has continued

to plague archeologists ever since:

who built this most incredible pre-Columbian city?

In the 1st century BC,

at an altitude of 2,275 meters,

men and women from Northern Mexico

crossed the semi-arid highlands

in search of a place to settle,

a journey that would lead them

all the way to the Valley of Mexico.

- I believe that there were people

back then who were geomancers.

Geomancy is a little-known gift.

Those who have it are able to determine

where a city should be founded.

- And they moved into the Valley of Mexico,

which is a rich, rich valley.

And because of the richness of the soils and so on,

they were able to pull people together physically

and still support them.

- An abundance that would draw

an ever-increasing number of migrants

to Teotihuacan in just a few decades.

- There were between 15 and 20,000 inhabitants,

which was already a large colony for that time.

And those men and women needed to be fed.

So they obviously had to figure out a way

to increase the yield of their crops.

- A soaring population that pushed city leaders

to rethink traditional agricultural practices.

A food shortage would have clearly been fatal

to the young city.

To increase food production,

they came up with an ingenious system of irrigation.

Fed by rainwater, two reservoirs,

each 500 meters long, 5.5 meters wide,

and 1.4 meters deep,

irrigated large expanses of agricultural land.

The water was pulled by gravity

into grooves carved into the bedrock,

which maintained constant humidity

in the thin layer of arable soil,

a complex system that allowed for multiple harvest annually,

much to the prestige of the city's elite.

- It's highly likely that the group

that oversaw the planning and construction of the system

started to gain more and more power.

- The political authority of Teotihuacan

is very well contested, right?

Some people say that it was a type

of collaborative rulership, and some say, no,

it was a very traditional autocratic rulership,

which one ruler that ruled resided over the city itself.

The reason we're contesting it so much is because

one, we don't have a writing system,

so we don't have a history of, you know, the Maya area.

They have lavishly engraved epigraphic records

of every ruler, every affair he had.

We don't have that at Teotihuacan.

The second thing is that

we don't actually have a burial of a king.

So, a centralized authority.

It doesn't have to be one person,

but it's much easier if it is.

So until I see evidence for the contrary,

I think it's really important to keep that in mind.

- Whether or not they shared their power,

the city's elites definitely had

some serious competition in the region.

The south was home to the Zapotec Empire

and the impressive city of Monte Alban.

To the east was the powerful Maya civilization

and its monumental cities of Nakbe and Calakmul.

And just a day away on foot to the southwest

was Cuicuilco, the largest urban center

in the Valley of Mexico at the time.

And all of these cities were home to monumental pyramids.

- Religion played a fundamental role

in the creation of the world

for the ancient people of Mesoamerica.

There's not a single city that wasn't built around a temple.

It was a central cohesive element.

- Pyramids are really artificial mountains.

They are able to bring to life, you know,

it's not just a mountain, but it's the mountain

where the ancestors' spirits are living.

That's how you communicate with your ancestors.

It's about being able to connect with the community

and the gods, and the whole ecological order

by building these mountains.

- Teotihuacan didn't simply want

to rival its powerful neighbors.

It wanted to dominate them.

To that end, builders needed to devise

a city unlike any other,

and make Teotihuacan the beacon of a new era.

The year was 50 AD.

The future city began to take shape around an immense road

that was two kilometers long and 70 meters wide,

the Avenue of the Dead.

This central access then branched into a network

of perfectly perpendicular streets and alleyways,

a city grid that foreshadowed large modern metropolises

like New York City or Beijing.

- It was urban planning

on an unprecedented level,

anywhere in the world.

That's why we consider Teotihuacan

to be the most perfect example of urban planning.

- They were like Martians.

I mean, they pulled in people

into this highly organized city on a grid system.

This was like nothing before

that would have required something like that

to be impressive, to make a statement,

a statement of power.

- A statement of power

illustrated by three sanctuaries.

The first, at a colossal 65 meters high

and 215 meters wide, was the Pyramid of the Sun.

With a volume of over one million cubic meters,

it's the biggest pyramid ever built in Mesoamerica.

- This pyramid was the megaphone of Teotihuacan.

This is what everybody looked towards.

No matter if you're a farmer

in the hinterlands of Teotihuacan,

you saw the pyramid, you saw what was going on.

You saw the smoke signal.

It doesn't matter where you live.

You will identify with the Sun Pyramid.

You will be proud to be part of this city,

so magnificent that it radiates its presence

throughout the whole valley.

- A pyramid, dedicated

to the most sacred star of Mesoamerica, the sun.

The structure was precisely oriented

15.5 degrees east of astronomical north.

The western wall is perfectly aligned

with the setting sun on August 12th,

which marks the beginning of the dry season,

and on April 29th, which marks the beginning

of the rainy season.

- They were sky watchers.

They were scientists and astrologers

that interpreted the sun,

predicted eclipses, understood the Venus cycle.

And so it's really incredible to understand

how meaningful this place was.

- The exact, you know, movement of the stars

and making their time system and so on, was astrology.

And you know, and some of these people say,

"Well, they could predict the seasons,

and when to plant."

That's quite ridiculous.

I mean, the farmers knew about this

a lot better than the kings.

And so these things had a religious meaning.

- A pyramid connected to the stars,

but also used to keep time.

That's because the Teotihuacanos designed the building

according to ancient Mesoamerican calendars,

the haab, comprised of 365 days,

symbolizing the solar cycle,

and the tzolkin, a ritual calendar of 260 days

divided into 13 months of 20 days each.

A complex calendar system,

which, thanks to a recent discovery,

has also been tied to the unit of measurement

used by Teotihuacano architects, the TMU,

a standard length of 83 centimeters,

corresponding roughly to the distance

between a human's fingertips and their heart.

- What's fascinating about this measurement unit

is that they actually tell us a little bit

about how they were able to materialize

what they saw into the sky,

and how they interpret that

physically into the walls, the rooms.

- Therefore, the 215-meter width

of the Pyramid of the Sun

corresponds to 260 TMUs,

the exact number of days on the ritual calendar.

The pyramid was surrounded by a 34-meter wide platform,

bringing its depth to 431 meters,

or 520 Teotihuacan measurement units,

twice the symbolic number of 260.

- When I say the Teotihuacanos were ingenious engineers,

I'm not kidding, you know.

They really were able to not only kind of make it look nice,

it actually really made you embody the cosmos

by just walking through the city itself.

That's what a better way to experience Teotihuacan

than embodying their understanding

of the whole world works through experience.

- But beyond symbolism,

the architects needed to figure out

how to erect such a massive monument.

To do so, they relied on an unexpected ally,

Popocatepetl, a volcano

located 100 kilometers to the south of Teotihuacan,

which had been forming the foundation

of the Valley of Mexico for thousands of years.

An almost inexhaustible supply of volcanic rock

was extracted by workers from dozens

of underground quarries all around the city.

- They quarry specifically this type of basalt,

which is locally called Tezontle,

and this Tezontle has a lot of pores,

so it's really lightweight and you can shape it very easily.

So it's easier to carry to you wanna build buildings.

That's why they preferred this type of rocks,

but they were not available on the surface.

They had to dig below the tepetate layer.

This is volcanic tough, and this is very soft,

as you see here, you can destroy it very easily.

And they crushed tepetate to make a base of the floor.

- In total,

some 715,000 cubic meters of this rock

was extracted from the earth

to build the entire city of Teotihuacan.

The material was then carried by men

on their backs for hundreds of meters.

That's because pre-Columbian civilizations

never domesticated animals to help them carry heavy loads.

- They compensated for the lack of pack animals

with an efficient use of manpower.

The people were the labor force,

and they were very effectively put to work

in a well organized way in order to be productive.

That's one of the characteristics

of Mesoamerican societies.

- The rulers of the city knew

they had an abundant supply of workers.

The population of Teotihuacan and its surroundings

was already at 80,000 inhabitants.

Men from each family were selected

to be part of the workforce.

- Religion played

a very important role in controlling

the people and the workforce.

That's something that had never been seen before.

It's very different from slavery, capitalism, or feudalism.

Here, you could own tools and land,

but they controlled the power of your labor.

- During the dry season,

tens of thousands of builders worked tirelessly

on the enormous construction of the pyramid.

Such a massive structure

could have very well crumbled

beneath its own weight.

To prevent that from happening,

a mound-shaped wall was built around the pyramid.

The interior of the structure was supported

with a grid of cells made of adobe bricks,

a mix of straw and clay.

The holes were then filled with dirt and rocks,

a process that was repeated layer after layer

all the way to the top.

This honeycomb structure allowed the building

to withstand the heavy weight

of the filling within the pyramid.

- Construction cells, they are not invented

at to Teotihuacan, but in Puebla.

And the reason why that technique

was developed or invented is unknown.

But I suspect that around 50 to 70,

there was a huge organic eruption of Popocatepetl.

And I assumed there was huge earthquake

and it is possible that many structures were destroyed.

Then those people possibly experimented

using different techniques.

And then finally invented

the technique of construction cells.

So, to keep those pyramids stable,

Teotihuacan people emulated or imitated those techniques.

- The Pyramid of the Sun

is the muddiest structure ever built by manpower alone.

How long did it take the Teotihuacano people to build it?

No one really knows.

Although many archeologists share similar beliefs

about the answer, a recent experiment

has shed new light on the conversation,

the construction of a miniature temple

using the same tools and materials from back then.

- We completed the whole process

in two weeks with four workers.

And the most intriguing thing

I learned through this process

is that we try to keep the walls flat,

but actually, we failed.

It was not possible for us.

I still do not understand how Teotihuacan people did it,

especially for large buildings.

So, based on our experiments, I calculated

the time necessary to complete the Sun Pyramid.

And I think it took less than 10 years,

and possibly around six years,

which is much less time than previously thought.

- An achievement that continues to impress

and puzzle archeologists some 2,000 years later.

How could the same people who built such structures

disappear without leaving behind any clues

about their identity?

South of the Avenue of the Dead,

beneath the Pyramid of the Feathered Serpent,

is the second main sanctuary in Teotihuacan.

15 meters below the surface,

a mysterious tunnel that was discovered in 2003

could unravel the mystery.

Entirely carved out with rudimentary tools,

this manmade cavity is covered in a thin layer of mud,

and follows an east to west orientation.

The tunnel stretches over 102 meters.

15 meters from the entrance,

a series of 23 walls, each one meter thick,

were built to block access into the tunnel.

- The tunnel was sealed three separate times

with walls that go from the floor to the ceiling.

Then they would destroy the walls to get inside again.

But we don't know for what purpose.

And then they'd rebuild new walls

on top of the remains of the old walls.

Later, they came back, but for some reason,

they left without rebuilding the walls.

Instead, they filled the tunnel with lots of dirt and rocks.

My theory is that for a period of time,

the end of the tunnel was used to store the remains

of someone specific, someone with a lot of power,

most likely a first era leader of Teotihuacan.

- Could this tunnel

have been the tomb of the Teotihuacan kings?

For the first time, archeologists seem

to be close to solving the puzzle.

At the end of the first section,

which is 65 meters long,

the narrow tunnel suddenly drops.

- The majority of the tunnel's first section

was dug about 15 meters below the surface.

And this here is deeper.

It goes down to 17 meters.

I think this whole section

must have been how they accessed

what we believe to be the most sacred

and important spot of the entire tunnel.

I believe it's the gateway to the real world,

the truth, and the real underworld.

- An intriguing sparkle in the rock

attracts the eye,

a phenomenon that's far from natural.

- The entire tunnel must have been covered

with this sparkling mineral powder.

It's made of three minerals:

pyrite, hematite and magnetite,

which were brought here from far away

and painted on these walls, the ceiling,

and even the floor of the tunnel.

It must have been an extremely important

religious experience to enter here in total darkness,

with only the light from your torch.

As the flame flickered, it must have looked like

the sky and the stars of the underworld.

- At the end of the tunnel,

three chambers facing east, south, and north form a cross,

the center of which is perfectly aligned

with the peak of the pyramid.

This imaginary vertical access

is called the axis mundi.

- There's a symbolic conduit here

that connects all three levels of the cosmos.

The entire world rotates around this vertical axis.

What continues to amaze us is how the Teotihuacanos,

this deep, were able to precisely calculate

how to perfectly align this point

with the summit of the Pyramid of the Feathered Serpent.

- Although no tomb was discovered here,

archeologists did make another incredible discovery:

four stone statues representing three women and a man,

all facing the axis mundi.

- We discovered the remains

of another sculpture, much larger than the four others.

It appears to have been a male figure.

It was naked like the others,

but all we found at this spot was a foot,

and 100 meters farther, a leg.

We believe that means that when the Teotihuacanos

came into this place, likely to desacralize

the tomb of the man who was buried here,

they also destroyed the sculpture,

which likely represented him.

From what we know, the Teotihuacanos were iconoclastic.

They destroyed the symbols of power

associated with a person at the time of their death.

- Sacred rituals must have been carried out here,

rituals like this king's ceremonial burial,

a man whose influence spanned far beyond the city's borders.

- When the funeral ceremony took place,

the entire Mesoamerican world sent gifts,

presents to accompany the dead king that was buried here.

It must have been a very important event

that affected the entire Mesoamerican world.

- Although the name of this king

has forever been forgotten,

the tens of thousands of offerings left in the tunnel

could provide important insights

into the Teotihuacan civilization.

They include objects made of jade or amber,

as well as finely carved shells,

many of which share something in common.

They're all from Maya civilization.

- There is nothing specific

to Teotihuacan here.

Everything is 100% Maya.

We've been able to decode them,

thanks to similar artifacts found on Maya sites

that are much older than Teotihuacan.

This glyph is very important.

It means ahau, and ahau means king.

It's most likely connected

to the structure of power in Teotihuacan.

That's why I think that the Mayas greatly contributed

to the creation of the ideology, the magical thinking,

and the religious identity of Teotihuacan.

The Teotihuacanos didn't create any myths.

They just borrowed the myths of the ancient Mayas,

and then they presented themselves

as the creators and the masters of the world.

But in reality, all the origins of this is Maya.

- The Mayas,

a people long considered to be pacifistic,

but who also practiced human sacrifice.

Was the Teotihuacanos' insatiable thirst for blood

inspired by the Mayas?

One thing is certain.

This pyramid, the last structure that completed

the historical heart of the city,

saw more bloody ceremonies than any other edifice.

- Located at the far north

of the Avenue of the Dead,

surrounded by 14 other pyramid structures,

lies the city's third key religious sanctuary,

the Pyramid of the Moon.

46 meters high, 149 meters wide,

and 168 meters deep, it is built on multiple levels

connected by monumental staircases.

It has been heavily explored

since the first Central American expeditions,

and 345 meters of tunnels have been dug here

in hopes of unraveling its secrets.

The excavations revealed incredible discoveries.

- The Moon Pyramid was constructed over a sequence of time.

So imagine an onion, it started off as a small dirt mound,

and then they built over and over

until it become larger and larger.

And so we know from doing tunnel excavations

at the core of the pyramid,

that there were seven building phases.

- The first pyramid,

which is only 23 meters wide,

was designed to support the second,

and the second supported the third.

This system allowed to limit the amount

of backfill needed for each step.

In total, seven pyramids were built

over three centuries at the northern limit

of the Avenue of the Dead.

- One of the most important kind of dimensions of the city

was the front of the Moon Pyramid itself.

It always had to start from that point

because this point to, for example,

the end of the Avenue of the dead

was a certain number of measurement units.

And so that's why they decided

that they always have to have the pyramid

start from this section.

- The Avenue of the Dead

is 2,156 meters in length, which corresponds

to 2,600 Teotihuacan measurement units,

meaning 10 times the number of days on the ritual calendar.

Striving to preserve the exact length

of the Avenue of the Dead,

the Teotihuacanos gave the Pyramid of the Moon

a very particular shape.

- Originally, it was kind of bound that grew three times.

When they build the fourth construction pyramid,

it becomes much larger.

It becomes what we know as a monumental scale, right?

So when they decided to add an adosada structure,

that's an annexed platform on top

of the main body of the pyramid,

they decide to cut the edges of the smaller mound

and then build another main pyramid behind it,

because that front had to be maintained.

So they're building over from the front, into the back.

- An important religious symbol,

the Pyramid of the Moon was key to the strategy

adopted by the leaders of Teotihuacan to make this city

the most popular site of pilgrimage in Mesoamerica.

- You could consider Teotihuacan

the great Mecca of Mesoamerica.

That's why we think this large street,

the Avenue of the Dead, which is over 70 meters wide,

was designed to receive thousands of people

from all over Central America.

- You could imagine that on certain locations,

you would have parades where people

will be looking onto the avenue,

all of the people walking into the dedicatory space,

the conch shells, you could hear them in the background,

but also the screeches and the roars

of the pumas and the eagles.

- And this would blow them away.

I mean, all those things painted now,

and they would go back and be impressed

and take some, you know, Teotihuacan influences with them.

- These pilgrims spread the word

of Teotihuacan's grandeur across all of Mesoamerica.

Thousands of them journeyed here

to partake in lavish ceremonies

that marked the start and end of each phase

in the construction of the Pyramid of the Moon,

rituals during which jaguars, pumas, eagles,

or even humans were sacrificed.

The great priest would finish off his victims

by ripping out their hearts.

The corpses were then buried in one of six burial chambers

within the pyramid's filling, all precisely aligned

along a north-south axis.

- The way that they are arranged

within the dedicatory space

is very important, both its orientation,

but also the quantity.

Certain numbers keep reappearing,

for example, certain calendric numbers,

like the number of days, months of years,

the number 18 comes up significantly.

It's the number of golden eagles

that were sacrificed in burial six.

Half of this number, nine were sacrificed in burial two.

I think so far, everything about Teotihuacan is intentional.

It's just incredible to think about

how they were able to conceive of such a master plan,

and not only think about it, but execute it.

- It was these three sanctuaries

that made Teotihuacan the most important religious center

in all of Mesoamerica,

and yet barely two centuries after its rise,

this city underwent a new revolution.

In 200 AD, Teotihuacan counted over 150,000 inhabitants,

making it the most populated city in Mesoamerica.

On either side of the Avenue of the Dead

and its lavish temples, entire neighborhoods

sprang from the earth.

These residential complexes, much like the great pyramids,

were subject to very strict rules of construction.

- The entire city was built around

the cosmo vision of Teotihuacan,

the four cardinal points, north, east, west, south,

and also in relation to the sun's position on certain dates.

The first city was oriented 11 degrees east

of the magnetic north.

And when I say city, I don't mean only the main road,

the Avenue of the Dead and its temples.

I also mean all of the structures,

all of the walls, the entire city.

- Tens of thousands of dwellings

that the new king wanted to tear down,

as the ruler wanted to impose a radical change

to the city's interpretation of cosmogony.

Reorient the city 15.5 degrees east of magnetic north,

a change that would lead to a large part of the city

being destroyed and rebuilt to fit the new layout.

- It was insane, as insane as destroying Paris,

Rome, or New York City, simply to reposition everything

by three degrees, which isn't even noticeable.

- This is a tremendous amount of planning, engineering,

and infrastructure to get it right.

Remember, they didn't have the total stations we have today

to make sure that alignment is completely accurate.

And the people residing in these locations

didn't just squat down.

And so it's amazing to think about

as far as what it took to convince

the already settled people to reorient,

because it's not just reorienting a building,

it's reorienting the way that you walk,

the way that you have access in and out

to the city center and in, right,

getting your way to the marketplace.

It orients your daily life in a very fundamental way.

- How could one king,

as powerful as he may have been,

impose such a radical change upon his people?

The answer lies perhaps within the structure

of the living quarters itself, an iconic part of the city.

Surrounded by a perimeter wall that limited access,

each complex included living spaces, storehouses, workshops,

and most importantly, a courtyard with an altar,

a central element controlled by the priest

where domestic religion was practiced.

- The priest controlled the production

of all objects made in this space.

They distributed the raw materials,

and collected many of the finished products,

which then they offered to the city's elite.

The weight of the local religion was felt on every level.

It was everywhere,

whether you were at home or in the biggest temples.

It was one of the ways that the elite

controlled the broader population.

- Like the great pyramids,

the entire city was painted in red pigment

extracted from a stone, hematite.

In the luxury dwellings reserved for the elite,

walls were decorated with ornate frescoes of scenes

strictly controlled by the state.

- The principal theme was this mountain.

It's an illusion to the Tlaloc, the god of the rain,

the most important god in Teotihuacan.

For example, in this part,

we see what appears to be a depiction of a sacrifice.

There are also decapitated heads.

It's obvious that this is more than

a simple decorative painting.

It is also a clear representation

of the Teotihuacano cosmo vision.

One of the ways they controlled the people

was by conveying the state's messages in stone.

- 2,200 living quarters

spread across 23 square kilometers

and overtook land that had once been used for farming.

To continue to grow their city,

the leaders of Teotihuacan made

what could be considered a surprising decision.

- Around 150 AD,

they closed all of the hydraulics,

which required great effort,

and they stopped cultivating their own food.

Why would Teotihuacan stop its own food production?

The Teotihuacan valley is actually very small.

So even if they had dedicated all the available land

to agriculture, that still wouldn't have been enough

to feed a population greater than 30,000 people,

but there were 200,000 men and women

living in Teotihuacan, which means

that most of the food consumed in the city was imported.

- A dependence that could become

the city's Achilles's heel.

The Teotihuacanos made a very risky bet

and decided to make the city the largest

artisanal production center in Mesoamerica.

To that end, they shifted their focus

to a strategic resource

that was widely available in the valley: obsidian,

the volcanic rock with exceptional physical properties.

- Obsidian obsidian is a volcanic rock

with very sharp edges.

It was the only material they could use

to make blades for sacrifices or weapons.

We believe there were numerous workshops in the city

that were dedicated to making objects out of obsidian.

We know that obsidian played an extremely important role

in the city's economy, and we found obsidian artifacts

in other places far away from Teotihuacan.

- Now the greatest economic power in Mesoamerica,

Teotihuacan attracted traders from all over Central America.

Entire neighborhoods of foreigners began to spring up.

The Zapotec neighborhood, located three kilometers

west of the Avenue of the Dead

was specialized in the production of stucco.

In the northwest, there was a neighborhood

that regrouped people from the Veracruz region

and the Maya lowlands.

- Today, Teotihuacan would've been

a multi-ethnic city, like New York City or Paris,

where people from all over the world dress

and speak in a variety of ways.

- It seemed like nothing could stop

the incredible growth of the city.

A regional power up until then,

Teotihuacan was about to take a new step

in its quest for domination.

The year was 200 AD.

In the Valley of Mexico,

Tlalancaleca and Cuicuilco,

Teotihuacan's biggest competitors

started to crumble.

No one really knows why.

And yet at the same time,

construction on a new pyramid in Teotihuacan

seemed to mark the end of a battle

of which the city emerged victorious.

- When the construction of the Pyramid

of the Feathered Serpent was set to begin,

a massive sacrifice of 260 people took place.

It's possible that they were prisoners of war

or rival leaders who were brought here and sacrificed.

There were placed at the base of the structure,

hands tied behind their backs.

They were all taller than average.

They all had weapons and were adorned with warrior symbols.

- Did this mass sacrifice signify

a change in the Teotihuacan power structure?

Built directly above the old tunnel,

this new pyramid was dedicated to Quetzalcoatl,

the powerful feathered serpent.

- Feathered serpent brings this emblem of time

and the creation of new time on its back.

And the way that this was materialized

is by embedding a whole military army

within the nucleus of the structure

where this feathered serpent is meandering

on its frontal facade, right?

So it's a very powerful message

that reflects the arrival of new rulership.

- A new sovereign had thus

taken control of the city,

an authoritarian leader,

whose goal was to make Teotihuacan

the first empire of Mesoamerica.

The new pyramid was meant to surpass everything

that had been previously built.

To do so, architects had to adopt a new style,

Talud-tablero.

This style uses an inward-sloping wall, the talud,

to support a vertical slab that's perpendicular

to the ground called the tablero.

This technique created significant areas of ornate facades

that further serve the state's propaganda.

- The Feathered Serpent Pyramid was very innovative

at that time period because of the integration

of three-dimensional sculptures with the building.

Originally, those sculptures were painted

with a lot of different colors,

including green, white, black, and also yellow.

Usually, Mesoamerican pyramids

were painted in just one color.

So I can imagine that those viewers were impressed,

highly impressed because they had not seen

the same thing before.

We think that those Teotihuacan elite

wanted two impress people by inventing something new,

which is associated with the new order

established with the building of this pyramid.

- Carved out of heavy blocks of andesite,

the sculpture seem to float on the sides of the building,

an illusory effect created by an ingenious system.

- In order to integrate three-dimensional sculpture

into the building,

they invented a new technology called tenon sculpture.

So here we see the serpent head,

and this part is called a tenon.

- In order to suspend the heavy rock,

a cantilever on one end of the stone

is slid into a hole in the side of the facade.

Within the pyramid, a chamber made of heavy stone

holds up the sculpture by counterbalancing its weight.

- So that sculpture does not fall.

This was unique in Mesoamerica,

and we don't see the same technology

before and after Teotihuacan.

- Previously conducted

in a highly intimate setting within the tunnel,

the rituals for the transmission of power

now took place in public.

To that end, the Pyramid of the Feathered Serpent

was incorporated into an architectural complex

of over 160,000 square meters

designed as an enormous stage, La Ciudadela.

Surrounded by a nine-meter high platform,

this closed watertight space was made to carry out

an incredible spectacle at the arrival of the rainy season.

- The myth were told about ancient times,

which no one can remember,

was that there was only water,

only the sea at first.

Thanks to divine intervention,

a sacred mountain rose up from the sea.

That moment marked the start of the calendar

and the passing of time.

We have proof that the Teotihuacanos flooded the square.

It was their way of representing the primitive sea

from which the sacred mountain had arisen.

- More than just a city,

Teotihuacan now embodied a myth,

the original place where the universe was created.

Its influence stretched far and wide,

from the Maya lands in the south

to the northernmost limits of the Mexican territory.

An empire, the size of which

would forever remain unmatched in Mesoamerica,

everyone thought Teotihuacan had become the supreme city.

- The square was huge.

According to our calculations, around 100,000 people

must have participated in the rituals.

We think it wasn't simply a ritual to mark

the passing of power among leaders in Teotihuacan.

It might have also been used by other governments,

and perhaps even Maya kings who came here

when it was their turn to be anointed.

- Ruler of Copan pilgrimed to Teotihuacan

to become enthroned as King of Copan.

K'inich Yax K'uk Mo' was at Teotihuacan

and went back and became the ruler of Copan.

So, it was an important voyage,

a religious voyage to create

your identity as the ruler himself.

- In five centuries, Teotihuacan had in turns

become a popular pilgrimage site,

then the biggest city in Mesoamerica,

and finally an empire.

A city built by hundreds of thousands of men

from all over Central America,

all convinced they were carrying out

the work of the gods.

And yet in 650 AD,

although no major construction

had been undertaken in over two centuries,

dissident voices seemed to rise over the city.

- Here we're standing

at the intersection of multiple streets.

You can see the sides of various residential complexes.

Suddenly, the roads were made narrower

and surveillance buildings were put into place,

to control who could access the various complexes.

It seems like the elite were trying so hard

to control the lower class people

that the latter probably began to rebel.

We think that conflict began to grow

between the two social classes.

- The repressive measures provoked

the anger of the Teotihuacanos.

A wave of violence started to spread in the city streets.

- It was violent.

There's a lot of burning.

And particularly, I'm talking about

the ceremonial center, right?

We have a lot of evidence of burning in various areas.

So, I do think it had to do

with a collapse with the central authority itself.

That is probably quite spectacular

because think about the scale,

and these are not wooden structures, right?

So they would' have required a lot of planning

and a lot of resources to complete the level of burning

that we see in the city itself.

- The elite overthrown,

Teotihuacan became no more than an empty shell

and its religious center collapsed into a pile of ashes.

The city's residents fled.

- We have proof that certain places

were abandoned very suddenly.

We found grindstones that they used to grind grain.

And when we removed them,

there was still corn meal residue on them.

The people must have fled quickly,

leaving behind anything heavy,

taking with them only what they could carry.

The migrants who had been living in Teotihuacan

returned to their native homelands,

taking with them the sole prestige that came

with having lived in the greatest and most powerful city

that had ever existed in Mesoamerica.

- Deserted, Teotihuacan

fell into oblivion for centuries.

But this incredible city

has not finished telling its story.

Rediscovered by the Aztecs in the 13th century,

it's become a place that touches anyone

lucky enough to visit its great pyramids.

After all, Teotihuacan is the birthplace of the gods.