A story wrapped in myth and legend

How did a tribe of wandering nomads

engineer the Americas greatest empire

in just 200 years

they had to devise engineering systems which 
were extraordinary for their age

Their civilization rivaled Rome 
in its sophistication

The Aztecs had the best technology 
that could be produced

in the conditions of which they lived

Acquaducts

Palaces

Pyramids

and temples stood as a 
tribute to their Gods.

and a testament to the power of human kind

The Aztecs crowning achievement 
was a gleaming capital city

That astonished European explorers called 
the Venice of the new world

The city spread out, 
glittering against its canals

and its lake be that with fine trees
and beautiful mansions

their thirst for power and blood set 
them on a course for destruction

When it finally came

their annihilation would be swifter

and more complete than 
the world had ever known

1325 A.D.

Central Mexico

Near modern day Mexico City

A young girl, just a teenager

is celebrating her impending wedding

She is the daughter of a tribal king

and she is about to join a new tribe 
that has been a guest of her kingdom

That tribe is now known as the Aztecs

As part of the ritual, five Aztec noblemen lead her 
to an ancient temple for the ceremony

But as she reached the top, 
noblemen suddenly veer her away from the altar

and onto a a slab of stone in front of the temple

one used for sacrifice

each man holds her limbs, 
while a fifth lifts an obsidian knife high in the air

with one searing move, he slashes it through 
her chest, and extracts her still beating heart

That evening, the king is invited to a ceremony to celebrate the marriage

Instead, he finds a 
priest performing a dance

wearing the still glistening skin 
of his daughter.

As part of the ritual, the Aztecs 
had flayed her to honor the God of fertility

He saw this and he was 
absolutely horrified at what he saw.

His dear daughter

He and his forces immediately 
chased the Aztecs into the lake

and onto this island 
where they sought refuge

The marshy island was an unwelcoming place

yet it was from here that the Aztecs 
would beat the odds against them

And forge the most powerful 
empire of the Americas

Hi. I'm Peter Weller. When I think of the 
Aztecs I think of an elegant people.

with beautiful skin and flamboyant 
headresses of many colors

and I think of floating cities 
and a terrific song by Neil Young.

About Montezuma and Cortez.

But I also think of knives of obsidian glass
ripping in the chest cavities

and hands pulling out bleeding hearts 
and holding them high

Most of the Aztec sacrifices were performed in 
the temple atop a stone pyramid like this one.

The Aztecs felt that without 
these offerings the sun would

literally cease to rise and the universe would die.

Now Aztec history is a fusion of fact and myth

but what we do know is that this murder as horrific as it was

not only marked the beginning of the Aztec empire

it also marked the location from where would rise.

The island the Aztecs were banished to after 
their disastrous sacrifice of the princess was in lake Textcoco.

The largest of five interconnected lakes 
covering a valley about 40 by 70 miles.

Today, this once vast and open valley

is teaming with what is modern day Mexico City.

One of the largest cities in the world.

But 700 years ago, the island was so 
swampy no one had laid claim to it

Now as they gazed on the lake.

The Aztec leader Tenoch announced to his followers

that he had seen an eagle, perched on 
a cactus in the middle of the lake.

A sign from the Gods that 
they had found their new home.

They would name their city Tenochtitlan.

Life is tough for the Aztecs 
in the early days of Tenochtitlan.

But they have a vision.

A vision of a powerful city

Modeled on an ancient and legendary city just 25 miles away

They called this city Teotihuacan

or "City of the Gods."

We know very little about Teotihuacan

because all we have is the archaeological remains

we don't have any writing we don't have any documentation

that really flashed out what went on in this big city.

It was in ruins even in Aztec times.

But they believed it to be the 
stomping grounds of the Gods.

And the literal birthplace of the sun itself.

The place the Aztecs most revered in Teotihuacan

was a pyramid that rose above the tree line.

It was called "The Pyramid of the Sun".

The massive Sun Pyramid contains 
a million cubic yards of earth and stone

with a base roughly the same 
as the great pyramid of Giza in Egypt.

The Aztecs believe Teotihuacan

was laid out in the image of the cosmos

created by their Gods.

Now it was this image they would 
attempt to replicate

in the construction of their new city: 
Tenochtitlan

Taking on the challenge would be an Aztec leader named Acamoaoichtli.

In 1376, he embarked on an ambitious plan to 
engineer an advanced city at Tenochtitlan.

But there was a problem.

The swampy islands that they took over 
needed a lot of work.

When they started to build anything 
it would begin to subside.

There was simply no foundation on which to build.

The Aztecs' solution would revolutionize the architecture of the Americas.

They began by anchoring their buildings deep in the ground.

Using a system of pylon made from wood.

Workers cut stakes into thirty foot 
lengths - three to four inches wide.

These were driven into the soft ground 
to make a foundation.

The pylons were often surrounded 
with volcanic stone to add strength.

Masons and bricklayers could then build 
walls on top of this base with confidence.

They have found wooden pilings to hold the foundation of the buildings

the fact that it didn't sink
or the fact that is didn't just topple

I think that's a major feat of engineering

Tenochtitlan was an island city

but the lakes surrounding it were very shallow

sometimes only seven feet deep

The whole thing looked like a giant 
metroplex floating on a pond.

Originally, the only way to get from 
this floating city the mainland was by boat

But the Aztecs eventually devised

a series of causeways sometimes 45 feet wide

that would connect their floating city 
to the mainland provinces.

The causeways were supported 
by strong wooden pilings

the same pilings that supported 
their temples and other buildings

thousands of these pilings had to be 
driven deep into the lake bed

and this presented a logistical challenge

that can only be met by a strong skilled labor force

and the best of Mesoamerica's engineers.

To build a causeway, two lines of steaks were laid out.

Then the space between them was filled 
with stones and earth

until it reached several feet above the water level.

This allowed the road to support enormous weight.

These causeways were built very straight.

They were very wide with 
bridges that would open up.

That connected the city to the north to the west

and to the south.

The roads enabled the Aztecs to transport 
larger heavier materials for building.

But this presented a new challenge

there were no beasts of burden in Mesoamerica so

everything had to be done with humans

no carts, no wheel

Small loads would be carried on the back 
with a rope hung from the forehead.

Large items like stone blocks or 
sculptures for a temple

would be dragged by huge numbers of men

pulling ropes, possibly using logs as rollers

Legend has it one stone bound for a temple
required the force of 50 thousand men

To drag it from the mountains on the 
mainland, across the causeway and into the city

The causeways would also present the Aztecs 
with a new way to get fresh water to Tenochtitlan.

In the past, the Aztecs had transported 
water in canoes from the shore.

But a huge boom in the city's population 
meant they needed a higher tech solution

to keep up with demand.

They wanted to use water from 
the springs on the mainland.

And so they wanted to build an acquaduct.

But the springs were under control of the 
dominant tribe in the region:

the ruthless Tapaneks.

The Tapaneks were the controllers or 
the dominators of all the valley.

They had a very strong empire.

So they were the lords of the valley.

So the Aztecs were tributary subjects to them.

As the Aztec population grew, 
tensions with the Tapaneks began to simmer.

Now the Aztecs decided to issue an ultimatum

that could change the balance of 
power in the region.

The people of Tenochtitlan not only demanded 
that the Tapaneks give them the water

but also demanded that they help 
construct the acquaduct.

The Tapaneks' answer was swift and brutal.

The Tapanek king Makstala sent assassins 
who murdered the reigning Aztec leader in cold blood.

This was the final straw.

After decades of domination, the Aztecs 
would finally make their move

and wage war against their ruthless overlords.

And they would launch a series of 
wildly ambitious building projects

around their growing island city

that would earn them a reputation 
as the greatest engineers of the Americas.

It is 1428, and the Aztecs have 
declared war on their overlords

a tribe calles the Tapaneks.

But to defeat the Tapaneks, they would need a little help from their neighbors.

The Aztecs approached the nearby 
city state of Texcoco.

There, a decisive leader was on the rise.

His name was Nezahualcóyotl

and his domineering leadership would 
be instrumental in forging the Aztec empire.

With Nezahualcóyotl at their side, the 
Aztec underdogs woud go for the jugular.

They launched an all-out attack on the Tapanek capital.

After a siege of more than 100 days,

they broke through Tapanek defenses and
slaughtered their oppressors.

After capturing the Tapanek king, Makstala, 
king Nezahualcóyotl personally cut out his heart

and sprinkled his blood into the waters of lake Texcoco.

Suddenly, the tables had turned.

That is the exact moment of the 
beginning of the empire.

And the Aztecs became the leaders of 
the valley of Mexico.

After conquering the valley of Mexico,

the Aztecs could now turn their attention 
to bringing clean water to their growing city.

Remarkably, the Aztecs would 
independently design and build

something a few world empires would master:

the aquaduct.

The aqueduct actually had two channels 
each about five feet high and three feet wide.

One would be cleaned and maintained 
while the other was being used

so the water flow was never interrupted.

The twin tube aqueduct ran for 
three miles from the mainland

to the center of the island city.

In town, water streamed into public 
fountains and reservoirs.

and was distributed to the public in 
large clay jars or by canoe.

In comparison to the Europeans, the Aztecs
were a very clean people.

We know that the Aztec emperor bathed twice a day.

So, in terms of higiene, the Aztec people 
was much more advanced than the Europens.

While the Aztec nobles were bathing in 
luxury, at this time in Europe, plague

caused by unsanitary conditions was killing millions.

King Nezahualcóyotl's own bath was 
one of the most unique in the Americas.

In was fed by a sophisticated aqueduct system 
that also brought running water to his palace grounds.

Behind me is the hill of Texcotzingo, and on this hill
Nezahualcóyotl built a fantastic treasure palace.

and around this palace a virtual 
botanical garden, filled with all

the exotic flowers of Mesoamerica.

Nezahualcóyotl brought water 
from the Sierra Nevada mountains

all the way down to here into this hill, 
to his palace just to water his plants.

To install an aqueduct there,

Nezahualcóyotl had to fill a huge gorge 
between Texcotzingo and the next will.

As the water arrived at the first hill,
it gathered in small pools

build to control the speed of the 
flow before it reached the aqueduct.

After crossing the aqueduct, the water 
ran in a circuit around Texcotzingo hill

Spilling off over the sides in 
rock-cut waterfalls

to water the gardens.

it ended up in a nearly perfectly round rock cut pool called the king's bath