NOVA

NARRATOR: For centuries, historians imagined the ancient Amazon as a wilderness-- no civilization, barely any people, nature untouched by human hand.

Archaeologists largely ignored it.

People just assumed that there was nothing here in the Amazon, and it wasn't worth looking for things here, so nobody came.

NARRATOR: But now, dramatic new discoveries are shattering those old assumptions.

MICHAEL HECKENBERGER: All of a sudden, we see something in the Amazon that had been assumed couldn't exist there.

NARRATOR: Huge ancient agricultural systems, urban centers over a thousand years old, mysterious monumental architecture.

(translated): This has changed our perception of ancient Amazonian societies.

NARRATOR: From the last ice age, stunning paintings left by some of the very first humans in the Amazon.

GASPAR MORCOTE: Ac estn plasmados... (translated): Here are captured the thoughts of many groups over thousands of years.

NARRATOR: Who were these ancient artists and builders?

What were the civilizations they created?

Finally, archaeologists are revealing the untold story of the "Ancient Builders of the Amazon," right now, on "NOVA."

NARRATOR: The vast Amazon.

Covering almost half of South America.

About two-and-a-half million square miles of tropical forest, the largest and most biodiverse rain forest on the planet.

It holds a third of all known terrestrial animal and plant species and about 20% of the planet's flowing fresh water.

The Amazon's natural history is spectacular.

But what about its ancient human history?

Great ancient civilizations flourished in other parts of the Americas, like the Maya and the Inca.

All built thriving cities filled with temples.

They reshaped the landscape to support huge agricultural systems, many still visible today.

But until recently, most scientists viewed the ancient Amazon as untamed nature-- a wilderness.

HECKENBERGER: It was pretty standard, the assumption of both the public and the scientific community that the Amazon was pretty much untouched nature, that human groups there were only small, relatively mobile groups living more or less one with nature.

CARLA JAIMES: Y durante muchos siglos... (translated): For many centuries, we thought that in Amazonia, civilizations and complex societies had just never developed.

If you look at the history of archaeology in South America, people just assumed that there was nothing here in the Amazon and it wasn't worth looking for things here, so nobody came.

And then this idea that there was nothing happening here in the past became very strong.

NARRATOR: The lack of complex societies in the Amazon seemed to have a good explanation: its poor soils made intensive agriculture impossible.

Without intensive agriculture, dense populations and complex societies could never exist.

This was the dominant argument for decades.

But now, a new generation of archaeologists is proving that wrong.

One of the scientists leading the way is Bolivian archaeologist Carla Jaimes.

She works in a remote area of the Bolivian Amazon called the Llanos de Mojos.

(birds twittering) JAIMES: Y debo admitir que la primera vez que... (translated): I have to admit that when they first asked me if I wanted to do archaeology in the Llanos de Mojos, it seemed really remote and inhospitable to me.

What are we going to find in the Amazon jungle?

Ya son... (translated): Now it's over 23 years that I've been doing research in the Llanos de Mojos.

And the more I learn about it, the more it surprises me.

NARRATOR: Carla's greatest surprise is that wherever she looks, she finds the remnants of an ancient culture-- especially when she looks at the landscape from the air.

(men speaking on radio) NARRATOR: On the edges of the rain forest, where jungle gives way to grasslands, geometric markings cover the plains.

JAIMES: Y de repente... (translated): And to suddenly see those marks on the earth, perfectly geometric, gigantic, in places where today there is nobody, this would make the mind of any archaeologist explode.

Who made them?

How long ago?

Why?

NARRATOR: Carla has devoted much of her career to those questions.

Slowly, she is getting answers.

Evidence suggests the marks are raised terraces probably constructed by ancient people to protect their crops from floodwaters.

JAIMES (translated): The terraces are 20 to 30 meters wide and 200 or 300 meters long.

They date from 1,600 years ago up to 500 years ago.

So they were functioning for over a thousand years.

NARRATOR: The terraces suggest intensive agriculture.

Could this be evidence of dense populations or even ancient cities?

In another part of the Llanos de Mojos, Carla has been investigating a number of hills covering the landscape.

JAIMES: Es increble la cantidad de cermica que se encuentra... (translated): It's incredible the quantity of pottery we find on the surface of these hills.

This, for example, is a fragment of a grater, which they used to prepare different foods like peppers, manioc, and corn.

Como los Llanos de Mojos... (translated): Since the Llanos de Mojos doesn't have any stone, the ancient people who lived here had to make many of their basic tools from pottery, like mortars and graters.

Esta cermica que encontramos... (translated): This pottery we find on the surface I calculate is about 800 years old.

NARRATOR: When she and her team started digging below the surface, they found so many artifacts, they concluded the hills were not natural at all.

JAIMES (translated): So here we are on top of Loma Perotom, which is one of hundreds of small hills in the southeast Llanos de Mojos.

100 years ago, people thought they were natural formations.

We now know they were constructed over 1,500 years ago.

NARRATOR: Rather than hills, these were giant, carefully built earthworks.

Along with the agricultural terraces, this was yet more evidence that ancient Amazonians were not just living on the landscape, they were actively transforming it.

JAIMES (translated): We now know that these societies left a huge mark on the landscape.

The Llanos de Mojos is a landscape that has been modified.

NARRATOR: Even knowing how ancient people transformed the landscape, Carla was unprepared for the amazing discovery her team made in 2019 at a large mound called Cotoca.

A menos de diez kilmetros de distancia... (translated): About ten kilometers from here is one of the biggest mounds of this region.

In 2019, we decided to do a lidar survey of it.

NARRATOR: Lidar is the remote sensing laser technology that's revolutionizing archaeology.

Lidar bounces thousands of tiny laser beams off the landscape and then assembles their reflections into a 3D image.

Forests and grasslands can then be digitally cleared away to reveal the hidden outlines of ancient human settlements beneath.

When the lidar images of the large mound were processed, Carla could hardly believe her eyes.

JAIMES: Lo que vimos fueron mapas de sitios... (translated): What we saw was the outlines of a place that was so big, we realized it was not just a single mound.

It was a collection of mounds that formed what we could call a city or some sort of urban complex.

It measures about 600 acres, and inside it there are at least 18 separate structures.

NARRATOR: Nothing quite like this had ever been seen in the Amazon.

It was a breathtaking discovery which reverberated around the world.

But was it really a city?

As archaeologists discover more evidence of ancient structures in the Amazon, debates arise about the nature of the societies that built them.

HECKENBERGER: In fact, many people didn't want to believe that there was anything like urbanism in the pre-Columbian Amazon.

Well, as time goes on and technologies improve, we start to see that, wow, these types of societies existed in many parts of the Amazon.

The only thing is, is, they don't fit our standard model of what an urban society would look like, based on models that come from deep in Western historical experience-- Egypt, Mesopotamia, Greece, and Rome.

NARRATOR: The lidar images of Cotoca show a huge constructed platform 16 feet high and spanning over 50 acres.

This was the focus of an extensive urban complex.

In its center was a huge 70-foot pyramid, which archaeologists believe was probably used for grand rituals and administrative functions.

This civic ceremonial construction dominated a network of settlements that spread out over the surrounding plains.

Working in another part of the Amazon, Michael Heckenberger was one of the first to describe this distinctive type of Amazonian settlement pattern.

We proposed that this indeed was a form of pre-modern urbanism.

That in fact, they didn't have cities, but the connections and networks-- very systematic and very tightly integrated-- of towns and villages had the same scale of impact, perhaps organized the same scale of populations, as people were accustomed to talking about in small to medium-sized urban civilizations elsewhere in the world.

NARRATOR: After the discovery of 2019, Carla is now expanding her lidar surveys, looking for yet more ancient settlements.

Como le va, seorita?

Bien, gracias.

NARRATOR: She works with the Indigenous people who still live in the forests of the Llanos de Mojos-- like Dionisia Noza, leader of the Mojeo Indigenous community of San Bartolo.

Dionisia and her family are probably descendants of the people who created the ancient urban complexes.

Sienten que tambin tienen una relacin con, con sus ancestros y con la gente que viva antes ac?

NOZA: Bueno nosotros sentimos porque le hablamos nosotros.

Nosotros sentimos que ellos nos estn ayudando, no ve?

Entonces por medio de eso sentimos el peso de que nosotros sentimos que vamos a poder, igual que ellos.

JAIMES (translated): I think there is something that is really changing in archaeology.

It is our commitment to return the results of our research to the communities where we work.

Before, research would be published in foreign languages in publications in other countries.

Now we make sure the publications come back here.

People want to have them translated and keep them in their own libraries.

NARRATOR: Before starting his flight, lidar expert Renan Torres explains the remote sensing laser technology to Dionisia.

He has the latest generation of lidar equipment, which is now so small, it can be mounted on a drone.

Este es un drone... (translated): This is a drone on which is mounted the latest lidar sensor, which allows us to erase the information about the trees so that what remains is only what has been modified by humans.

NARRATOR: Carla has already made amazing discoveries with lidar.

She hopes for more.

She suspects that buried beneath the jungle around the village of San Bartolo are more traces of ancient settlements.

She is looking for the telltale raised-earth platforms created by ancient peoples.

(crickets chirping, wildlife calling) That night, when Carla and Renan study the 3D image of the rain forest around San Bartolo, their expectations are surpassed.

When the vegetation is stripped away, they can clearly see that the present-day village is actually built on an ancient human-made platform.

JAIMES (translated): So the platform looks rectangular-- 200 meters by 500 meters and about three meters high.

And there are in fact two platforms.

NARRATOR: So there has probably been a community where Dionisia and her family live today for a thousand years.

It was one of the many small satellite communities of the ancient urban network of the Llanos de Mojos.

This existed right up to the time of the arrival of Europeans in the 16th century, the end of the era of the ancient Amazonians.

When did that era begin?

Until recently, nobody was sure.

But in the Colombian rain forest, extraordinary evidence of the arrival of some of the first humans in Amazonia is being found.

Archaeologist Gaspar Morcote has made the search for those first Amazonians his life's work.

In an area of mountainous jungle called La Serrana de la Lindosa, he and his team have been finding traces of ancient human activity everywhere.

MORCOTE: Este es uno de los caminos de mayor antigedad... (translated): This is one of the oldest pathways of those first humans in the Amazon rain forest.

NARRATOR: How does Gaspar know they were here?

The clues are in the physical remnants those early Amazonians left behind.

MORCOTE: Hemos encontrado las evidencias... (translated): We've found the traces they left.

Traces of bones, their food, pieces of fruit, their fireplaces, and their stone tools.

NARRATOR: When Gaspar's team radiocarbon-dated those traces, their age astonished him.

Muestran que hace... (translated): They show that 12,600 years ago, human groups arrived in this area of the jungle.

NARRATOR: It means that humans were here towards the end of the last ice age.

Este es un sitio que est ubicado en estos aleros... (translated): This is a site in one of the rock shelters which were typical places those first inhabitants of the Amazon used.

And this is a type of soil which we can read like a book.

Y ac nos cuenta la historia... (translated): It tells us the story of those first inhabitants and all of the generations that came after.

That whole story is here.

NARRATOR: The story told by these soils is of the nomadic hunter-gatherers who arrived here over 12,000 years ago, some of the earliest confirmed evidence of people in the Amazon.

They used this rock shelter as a temporary campsite.

MORCOTE: No tenan cermica.

(translated): They didn't have pottery.

They were nomadic groups who wandered the jungle living from what they hunted and the fruits they could gather.

NARRATOR: The tools and food remnants left by those early Amazonians tell Gaspar the story of their way of life.

But other traces they left behind are much more dramatic.

To reach them requires a journey by river.

The Guayabero River is born in the High Andes.

Its waters squeeze between the high rock walls of the Serrana de la Lindosa before flowing down into the jungle.

Scientists think that humans first came into South America through the Isthmus of Panama.

To get into the Amazon, some had to cross the Andes, and Gaspar believes that the Guayabero Canyon provided those early travelers with a natural entry point, through the mountains and down into the rain forest.

MORCOTE: Un portal donde... (translated): It was a gateway through which those first humans came down from the Andes and started to colonize the Amazon basin.

NARRATOR: There is no way of knowing all the different pathways people took on their way into the Amazon, but dramatic evidence reveals this was clearly a very important one.

Because those ancient travelers covered the cliffs of the low mountains of La Lindosa with painted figures.

Thousands of them.

MORCOTE: Este es un mundo fabuloso que la gente antigua... (translated): It's a fabulous world that those ancient people painted here.

They represent the animals they lived with and the plants they lived with.

Ac estn plasmados... (translated): These figures capture the thoughts of many groups over thousands of years.

Muchas figuras que pueden plasmar la magia... (translated): Some of the figures seem to represent the magic and shamanism of their rituals, but there are also geometric figures and human figures.

NARRATOR: The ocher pigments contain iron oxide minerals from the earth.

Even though their exact meaning is not clear to Gaspar, he feels the paintings express a profound kinship with the natural world.

MORCOTE: Eso no es como hoy da... (translated): Unlike us today, who feel we are separate from the jungle, those people were part of it, along with the rest of the animal and vegetable world; just another being of the jungle.

NARRATOR: Along with the figures of humans and animals of today's rain forest, like deer, tapirs, and jaguars, there seem to be animals that went extinct thousands of years ago.

It is a reminder of just how ancient some of the paintings probably are.

MORCOTE (translated): We are talking about 12,600 years ago.

At that time, there was a fauna that no longer exists in South America, like mastodons and the American horse.

...que todo este tipo de fauna convivi, vivi con la gente, con los humanos... (translated): All of these animals lived with humans up until about 10,000 years ago, when they started to go extinct.

...pensamos nosotros, que existen tambin animales... (translated): So here, we think, there are animals of the last ice age, like the giant sloth right behind me.

NARRATOR: The painted cliffs of La Lindosa open a remarkable window on the lives and minds of the first ice-age Amazonians.

At their nearby habitation sites, Gaspar and his team have also discovered evidence of how their lives changed over the millennia.

The only tools the earliest nomadic hunter-gatherers left behind were made of stone.

(translated): This was their way of life up until somewhere between 4,000 and 6,000 years ago.

Posteriormente mas o menos ac... (translated): About here, at 70 centimeters down, we start to find the people with agriculture.

These are the people who domesticated plants.

NARRATOR: In levels dating to less than 6,000 years ago, Gaspar starts to find evidence of manioc and peach palm cultivation.

Other research has shown that early Amazonians also planted cacao, tobacco, papaya, and chili peppers.

Todos los trabajos de las ltimas, de los ltimos 20 aos... (translated): Work in the last 20 years has shown that Amazonia is an independent center of plant domestication.

Manioc is a great example.

Su experimentacin inicial... (translated): We know that the first experimentation in domesticating it began 8,000 or 9,000 years ago here in Amazonia.

It is the same with cacao, tobacco, coca, and papaya.

NARRATOR: But how could early Amazonians grow all these crops?

It has long been known that the soils of the Amazon are naturally sandy and acidic.

Nutrients in the topsoil are absorbed by the dense vegetation or leached away by the constant rain.

This is what led archaeologists to believe intensive agriculture, and therefore large populations, were impossible in Amazonia.

HECKENBERGER: When I came into the field, it was widely assumed that Amazonian soils were not particularly fertile, they were difficult to work, and would not provide the type of productivity that could support large populations based on agriculture.

Well, we've come to realize that not only are Amazonian agricultural systems very diverse, use a wide variety of crops, fruit trees, but they also focus, as often as not, on root crops, rather than seed crops, like corn or wheat or rice.

And it turns out that manioc, the primary root crop, actually does quite well in Amazonian soils.

NARRATOR: But what about the other crops that early Amazonians planted, like cacao, tobacco, coca, and papaya, that require more fertile and less acidic soils?

By the banks of Brazil's Rio Negro in the northwest Amazon, a team of Western and Indigenous archaeologists is investigating the soils of an ancient Indigenous community.

(rain falling steadily) Led by archaeologist Manuel Arroyo-Kalin, they discover a thick layer of dark earth quite different from normal jungle soils.

(speaking Portuguese) (translated): It is a loose, rich earth, which is fantastic for cultivating, because it's very fertile.

In fact, we are finding pieces of bone in it, which tell us that its pH is higher, more alkaline, than usual in acid jungle soils.

It is probably close to pH neutral, which is why it preserves bone material much better.

NARRATOR: This rich dark earth is called terra preta, and it does not exist naturally in the Amazon.

Ancient people had to create it by carefully composting ash, crushed bones, pottery shards, and vegetable refuse into the soil around their communities.

Over generations, this transformed the acidic jungle sands and clays into the rich dark soil that could sustain intensive agriculture.

Tucano archaeology student Jurandir da Silva is fascinated by how his ancestors created terra preta.

(Jurandir da Silva speaking Portuguese) (translated): They transformed the soil according to their needs, over many years turning refuse into the soil, letting it decompose, and then putting more and more on top.

And with time, the terra preta becomes really fertile and productive.

People still use it today for their agriculture.

HECKENBERGER: It turns out human activities, just basic refuse activities, and the upkeep of houses and villages incorporates materials into the soil that make them more fertile, that make them more suitable for agricultural production.

(birds chirping) NARRATOR: Ancient Amazonians clearly understood the value of this composting.

They used it to transform jungle soils so that they could support intensive agriculture and large populations.

NEVES: These production strategies, they were good enough to keep the people living together-- we're talking about hundreds or thousands of people-- for a long time in the same place.

NARRATOR: As well as creating fertile soils around their communities, ancient Amazonians also carefully managed the rain forest.

(wildlife chittering) They gathered certain trees, like peach palm and Brazil nut, in groves, where they could be visited occasionally and their fruits harvested.

To this day, even very remote parts of the Amazon bear the mark of this ancient forest management.

What Europeans imagined as pristine wilderness was in fact for millennia a semi-domesticated landscape.

La gente lo que hace con las plantas es... (translated): What those people did was to propagate certain species, concentrating them in a few places.

...de selva con una cierta... (translated): And so we see a jungle that is a mosaic of species which is the product of their work.

...trabajo, lo que vemos hoy en parte es... (translated): What we see today is the fruit of human actions that managed the forest without destroying it.

(Helena Lima speaking Portuguese) (translated): The latest research shows that the landscape and much of the biodiversity of the jungle was created by the Indigenous community that lived here in the past and still live here now.

NARRATOR: More than 80 species of plants were domesticated or semi-domesticated by ancient Amazonians.

That process began about the same time as the so-called Neolithic Revolution in the Middle East.

But it was very different, and led to different results.

NEVES: Typically, an archaeologist would say, "Well, these people, they never really completed "the full Neolithic cycle.

"They never really became fully formed farmers."

But what archaeology tells us today is that that perspective is not right, that these people were building their whole histories based on a different perspective, on a different logic.

NARRATOR: In the Middle East, plant domestication was based upon a handful of crops, such as wheat and barley, which could be easily stored.

The accumulation of surpluses and the development of huge irrigation systems that had to be administered led to forms of centralized political control.

From these arose the first cities and empires.

In Amazonia, it was different.

The need for irrigation was minimal.

The humid climate made storage and surpluses impossible.

So, highly centralized urban settlements never developed.

What emerged were towns and chiefdoms with populations in the tens of thousands, but not grand cities and empires.

There was not just one ancient Amazonian culture, but many.

They appeared all along the Amazon River itself, from the Guianas in the north to the Xingu in the south.

All distinct, all with their own unique styles.

One of the most remarkable is from the high jungle of Peru, at a site called Monte Grande.

QUIRINO OLIVERA: Siempre el punto crtico... (translated): Always, the central point of the scientists of the academy was that in Amazonia, there was no monumental architecture.

There was no evidence of organized populations capable of building monumental architecture because they thought they were just hunter-gatherers.

NARRATOR: Peruvian archaeologist Quirino Olivera had always wondered about the strangely symmetrical mounds by the banks of the Maraon River, a tributary of the Upper Amazon.

They seemed natural, but could people have constructed them?

In 2010, he started to excavate a similar mound on the outskirts of the nearby town of Jan.

It is the rainy season in the high jungle, so every night, they must cover the site to protect it, then uncover it the next morning.

OLIVERA: En el ao 2010... (translated): In 2010, we started archaeological research on a mound that, up until then, had been completely neglected.

We had no idea that we were on the verge of a discovery so important.

NARRATOR: Quirino has been excavating the site at Monte Grande ever since.

It is one of the most extraordinary and baffling archaeological finds of recent years.

Ese detalle de sacar capa por capa nos llevron a identificar... (translated): As we cleared away the top layers of soil, we began to see stones in a circular arrangement.

Then platforms and terraces began to appear.

That really surprised us-- it seemed extraordinary.

NARRATOR: As the full structure emerged, their surprise grew.

Here was a massive pyramid, as tall as a five-story building, constructed from clay, stone, and reed, with a mysterious stone spiral built on its summit.

The carbon-14 dates were even more astonishing.

The pyramid was built over 5,000 years ago, even before the pyramids of Egypt and Mesopotamia, a time when archaeologists had believed the Amazon was populated only by hunter-gatherers.

The find is so important, Quirino has invited famed Brazilian archaeologist Eduardo Neves to visit.

No creo que estoy ac!

Verdad!

Que alegra!

Que lindo.

Permiso, pasar para hacer una pequea ceremonia que tenemos ac.

Claro, si.

Por tu llegada.

(both laughing) Que lindo, Quirino!

He visto tantos fotos de ac, imgenes.

(inaudible) Y ahora finalmente estar ac... Si, es una maravilla.

(inaudible) NARRATOR: Quirino is of Indigenous descent and celebrates the occasion with an offering to the Pachamama, goddess of the Earth.

Salud, bienvenido.

NEVES: To be here at Monte Grande, for me, it's really like a dream fulfilled, because I've been teaching classes on South American archaeology for many years, on Amazonian archaeology, and of course, I know of Quirino's work, but being here is a total different story.

You can have a feeling about the power of the place, where it is located in this valley, surrounded by the mountains.

This is a very important site.

It's one of the most important archaeological sites that we have in the Americas, not only here in South America.

NARRATOR: Monte Grande rewrites the history of complex societies on the continent.

For over a century, when archaeologists wrote about cities and high civilization in South America, they focused on cultures like the Inca of the Andes or the Nazca of the Pacific coast.

But here at Monte Grande is clear evidence of a complex society and monumental architecture at least 3,000 years older than either the Inca or Nazca.

NEVES: If you compare the evidence from early architecture, of monumental architecture, of plant domestication, we see a lot of things happening before here in this part of Peru, in the Amazon, not in the coast and not even the mountains.

So I think it really brings and highlights the importance that the place that Amazonian Indigenous people had in the deep cultural history of this part of South America.

NARRATOR: The excavation of an almost identical but much smaller spiral pyramid in Ecuador revealed a tomb.

This makes Quirino think that Monte Grande also is the tomb of a religious leader.

If he's right, it would give meaning to the mysterious spiral so carefully constructed on top of it.

Porque el espiral es... (translated): The spiral is one of the most ancient symbols in the history of humanity.

It signifies the beginning and the end of life, the endless creation of one generation from the preceding one.

Yo estoy sentado en el centro de la arquitectura en forma de espiral.

(translated): I am sitting at the center of the spiral architecture, and right beneath me, in the spiral's center, would be the tomb of that high-status individual.

Suponemos que est... (translated): We believe that he is seated in a fetal position.

And from the center of his head, the spiral expands out like the axis mundi, the axis of the cosmos.

Y eso adems tiene un concepto astronmico, probablemente por... (translated): This also probably had important astronomical associations, as in most ancient societies who studied the night sky, the stars, and linked them to life on Earth.

(flames crackling) (Eduardo Izmio speaking Awajn) (translated): In the beginning, everything was in darkness.

(continues in Awajn) (translated): There was no fire and no light.

(continues in Awajn) (translated): The only one with fire was a being called Iwa.

(continues in Awajn) (translated): So, before the world could begin, our ancestor had to steal fire from him.

NARRATOR: Quirino believes Monte Grande embodies profound beliefs about life, death, and the cosmos.

The creation story of today's Awajn people does, too.

It tells of a primordial time when people and animals spoke to each other.

Through their adventures, the world was born.

(flames crackling) The story is told by Eduardo Izmio, Awajn elder, and his wife of many years, Teresa.

They live nearby, and have often wondered about the people who built Monte Grande.

They don't feel related to them, but are impressed.

Este trabajo, que nos da?

Qu nos ensea?

(translated): So, what does this place teach us?

It's clear that in those times, there was no money, but there was hunting and fishing, a lot of it.

The people ate very well.

There was a lot of solidarity.

This required a lot of work, a big communal work.

They were living from hunting and fishing, and here, there was a lot of people: children, young people, adults.

That was in those times, working together.

(translated): One person could never do all this.

NARRATOR: Eduardo and Teresa are not the only ones to marvel at the achievements of the ancient peoples of the Amazon.

Evidence of them is being found from the Atlantic to the Andes.

Not hunter-gatherers living in a tropical wilderness, but sophisticated cultures.

The hidden history of the lost civilizations of the Amazon is being unearthed.

What happened to those ancient Amazonian farmers and builders?

Most scholars estimate that within 100 years of their first contacts with Europeans, about 80% of the Indigenous populations died, killed by epidemics of European diseases to which they had no immunity.

Violence by settlers and rubber tappers killed even more.

Perhaps as many as eight million people died.

The great urban complexes and agricultural systems of Amazonia were reclaimed by the rain forest.

The pristine wilderness that many Europeans imagined was in fact a landscape emptied of most of its former inhabitants.

(wildlife chittering) (horn honks) Today, an estimated one-and-a-half million Indigenous people live in the Amazon.

In 1492, there were many, many more.

HECKENBERGER: And the scale of population in the Amazon has been a question that has drawn a lot of attention for, um, a long time.

But overall, the estimates generally range today between about five and ten million people in the Amazon basin.

NARRATOR: The scale of the destruction brought about by the conquest has given archaeology's exploration of the past extra relevance to Indigenous people.

In the city of S�o Gabriel da Cachoeira, on the Rio Negro in the Brazilian Amazon, Indigenous archaeology students are learning their craft.

(Ana Keila Fontes da Silva speaking Portuguese) (translated): I want to get involved with archaeology, and I do it so I can learn the story of my people.

These days, my people are interested in reclaiming the history of our Indigenous Tariano community.

(speaking Portuguese) (translated): Learning how we got from the past to where we are now, and into the future.

(Jurandir da Silva speaking Portuguese) (translated): For me, it was very important to do this archaeology workshop, because it looks at the origins of my own people, way back in time.

(people talking in background, soil sifting) NARRATOR: Archaeology student Odanilde Freitas has been studying granite rocks in the rapids of the Rio Negro.

Centuries before the conquest, ancient people carved mortars and grindstones in them to sharpen their fish spears.

(Freitas speaking Portuguese) (translated): Here we have a polisher and circular bowl.

(speaking Portuguese) (translated): Here we have sharpening stones-- two in one-- where the people sharpened their arrows and spear points.

NARRATOR: Oda's archaeological work has made her think about the history of her people, a history almost erased by colonization.

(translated): There has been a big impact in our culture from the centuries of colonization, but with archaeology, I feel we can rescue and reconstruct our identity, our Indigenous history, through artifacts like this.

(crying, speaking Portuguese) (translated): Excuse me.

I'm sorry.

It's because those people were free.

They were really free.

My people suffered.

They disappeared.

Imagine how they were massacred.

Sadly, that's the word.

They were massacred, they were raped, physically, culturally, psychologically, emotionally.

So that makes me sad to think about the past.

For me, it's very sad.

NARRATOR: The sadness Oda feels echoes the tragedy of Indigenous people all over the Americas.

Archaeology offers a reminder of what was lost.

But some Amazonian people today also feel that the recent discoveries help establish their rights to the land they have lived on for millennia.

As their forest is cut down for mining, cattle pasture, and soy fields, many Indigenous people are turning to archaeology to support their cause.

Kalutata Kuikuro is an up-and-coming leader of a group that has become iconic of Indigenous Amazonia and the struggle for its preservation: the Kuikuro.

(speaking Portuguese) (translated): Today my people understand that archaeology is important.

(speaking Portuguese) (translated): Every day, we're being pressured by ranchers and White people, so we believe that archaeology and understanding our history is part of our political struggle.

NARRATOR: So archaeology today is not just about the past.

It is bringing together scientists and Indigenous people in a common cause: the future of the Amazon.

NEVES: I think that the combination of the so-called scientific approaches with this more politically engaged archaeology done-- you know, the decolonialized archaeology done-- by Indigenous and non-Indigenous people, it's going to make archaeology more powerful and more relevant and more interesting.

Y creo que casi todos nosotros tenemos tambin... (translated): I think all of us have something very important in our thinking, which is our commitment to Indigenous communities.

Y estamos en momentos muy difciles en la Amazona.

(translated): We are in difficult times in Amazonia, because it's being destroyed.

This is what is bringing us together, thinking about how the past can help us oppose the destruction which is now so systematic in Amazonia.

NARRATOR: The revelation that for millennia, the ancient Amazon was home to complex civilizations is a reminder that humanity and the rain forest can coexist.

They did for thousands of years.

They can do so again.

MORCOTE: Estos grupos humanos no impactaron... (translated): Those ancient human groups were not detrimental to the forest.

On the contrary, they were managing the forest.

Entonces creo que es una enseanza, un legado... (translated): So this is a lesson, a legacy, that those ancient humans have left us.

They can teach us so much.

Let's see if we can learn from them.