The Amazon rainforest
stretches for millions of kilometers,
hiding ancient tribes, animals
and maybe something else.
What if under this mysterious canopy
lies an advanced civilization?
In the 1500s,
Spanish explorer Francisco de Orellana
returned from the Amazon
with wild tales of a golden city
called El Dorado
and warrior women in the jungle.
But when others
searched for treasure and glory,
they all came back with nothing.
So what the heck?
Did de Orellana make it all up?
Well, for the next few centuries,
that's what we thought.
But now, thanks to technology,
it looks like this explorer wasn't lying.
Using sophisticated aerial sensors,
researchers created a 3D image
of the ground under the rainforest
revealing a hidden ancient city.
That flies in the face of everything
we thought we knew about the Amazon.
The Amazon is the size of India,
and much of it lies beyond our reach.
Without this technology,
we might have never seen
what lies beneath the ground.
So what else did we learn?
Humans flourished
in the Amazon Basin
for almost 10,000 years.
And they weren't living
in the tiny mud huts
like you may have seen in movies.
These sprawling cities
could've held nearly one million people
in their prime.
And if these complex,
sophisticated people lived today,
the history of the world
would be radically different.
The Amazon belonged
to the Casarabe people.
And they didn't
just adapt to the jungle.
They might have created it.
Well, that's the theory anyway.
Researchers think that
this society built garden cities
around the plant life they selected.
Throughout the area,
the Brazil nut tree dominates the land.
Is that a coincidence,
or is this how the Casarabe
fed their people?
Still not convinced?
Well, the soil found in the Amazon
contains nutrients
not found anywhere else on Earth.
Called terra preta,
this dirt contains microbes
that fertilize barren land.
But while we think humans created this,
we still don't know exactly how.
Okay, well, so what do we know?
Those images showed us
they built villages in geometric patterns.
They clustered small communities
around larger ones.
Roads connected these settlements,
and they even constructed waterways.
Waterways that could've controlled
seasonal floodings
to grow crops and farm fish.
These intricate Amazon cities
are older than anything
the ancient Greeks built.
But what else did researchers find?
Well, for one,
it looks like these lost cities
aligned with the stars.
This means these builders
had advanced knowledge of astronomy.
The Casarabe built a civilization
that rivaled anything on Earth at the time.
So what happened to them?
Well, we still don't know.
But remember, these people
depended on flood waters
for almost everything.
If water became scarce
during a drought,
much of their civilization could've died out.
And whatever happened,
they were gone for 100 years
before the Spanish arrived.
Just enough time for the jungle
to reclaim their once-great society.
But if the Casarabe survived,
they could've grown even more advanced,
learning more about math, science
and astronomy.
They might have even fought off
the European conquest of South America.
Masters of the land,
these experienced jungle warriors
could have created
alliances with other cultures,
like the Aztecs or Incas.
This army might have changed
the face of history as we know it.
And if the invaders
and the Casarabe called a truce,
maybe the two societies
could have traded knowledge.
The people of the Amazon
could've integrated European transportation methods
and weaponry into their everyday lives.
While diseases like smallpox
would still have been devastating,
they might have developed medicines
or immunity to fight it off.
More importantly, all the minerals
and precious materials
hidden in South America
would have remained in South America.
And Spanish wouldn't be
the third most spoken
language on the planet
because these citizens
would proudly speak in their native tongue.
The nations we know now
could be completely different,
united under an Amazonia culture.
But hey, that could still happen now.
Like what if South America
became one country?
Stick around, because
that's a story for another WHAT IF.