Amazon Unnatural Histories

If there ever were a place on Earth

we'd expect to be pristine...

..it's here...

the Amazon.

Covering an area the size of Australia,

the region is a world icon of biodiversity.

And more than this, the Amazon's complex ecosystem has a global impact.

The forest acts as a huge carbon store

and generates patterns of rainfall way beyond its own borders.

Which is why the eyes of the world are fixed on the environmental war

between developers and conservationists.

One side is pressing to exploit the region to satisfy the world's hunger for timber, beef and soya.

The other is fighting to preserve what they see as the largest remaining wilderness on Earth.

But new discoveries are challenging the basic beliefs of both sides in this battle.

Many people still today have an image of the Amazon as pristine forest.

Archaeology is showing us a very different image.

There are archaeological sites in the Amazon which are larger than contemporary cities,

which suggest something like around five to six million people in the Amazon in the 16th century.

The idea of an essentially untouched environment is being questioned.

Since the first humans started settling into the Amazon, they started transforming the environment.

To many, these new ideas are down right dangerous.

It's misreading history, for one thing, and it's encouraging the developers to come

and denude it because they say if it was done once they can do it again and it'll all grow back.

But to others, the truth is not negotiable.

One thing we know is that there were, in pre-history,

complex societies from the north, south, east and west.

And the bottom line is that to deny that is to deny the reality of the Amazonian past.

With the threats to the rainforest ever increasing,

there is much riding on how natural the Amazon really is.

Is the forest virgin or man-made?

Since Europeans first encountered the Amazon in the 16th century, it has presented an enigma.

Sometimes it appeared to be a lush paradise, and sometimes a green hell.

It's been seen as a place abounding in life,

but also as a hostile emptiness.

The history of humanity's dealings with these mysterious forests

has been a history of shifting ideas.

It's the last wilderness,

it's a business opportunity,

it's the lungs of the planet.

And every so often a new idea appears and surprises everyone.

This is the first documentary ever made in the Amazon.

It was shot in 1922 by a Portuguese filmmaker called Silvino Santos,

and it astonished its audience.

It showed an Amazon teeming with human activity.

He showed an Amazon that was populated, full of production.

It had all sorts of fish,

it had rubber, it had Brazil nuts.

We have a scene of a factory. It's amazing, you know, the way that Silvino shows that.

Even today people don't believe it, you know?

People don't believe that that's the Amazon.

This film was the first challenge to popular notions of the Amazon

as a sparsely populated, virgin wilderness.

It's really a modern region, you know?

It's not something that is from another time, because that's another vision of the Amazon, isn't it,

it's something that's pristine, you know, it's from another era, really.

The popular vision of the Amazon as pristine

dates back to the period after the Age of Discovery, when Europeans had encountered unfamiliar new lands.

These sorts of concepts of pristine really had to do with their conception of land tenure,

so if they didn't see people actually fencing in the land,

cutting all the trees down, burning up the land and converting it into,

say, cattle pastures or other sorts of major landscape transformations,

then they often didn't consider there to be any kind of land use

going on and therefore these landscapes could be called primeval, pristine, virgin, what have you.

In Latin it was called terra nullius, the land of nobody.

Von Humboldt was one of several naturalists with that kind of idea.

Alexander Von Humboldt was a German scientist and explorer who promoted the idea

of the Amazon as a virgin paradise after visiting the region in 1800.

He'd been impressed by the sheer abundance of the forest.

"One may almost regard man

"as not being essential to the order of nature.

"The earth is loaded with plants,

"and nothing impedes their free development.

"Here, in a fertile country, adorned with eternal verdure,

"we seek in vain the traces of the power of man."

In Humboldt's mind the indigenous people had no lasting impact on the forest in which they lived.

He encouraged a number of artists to visualise his highly romanticised view of the Amazon

and its people.

The indigenous people are grouped in with nature itself as if they are part of the background

scene to a pristine environment, and that gives us in the case of the Amazon - which, indeed, had very

low population density, scattered settlements of forest peoples - a seeming aura of

primeval nature, untouched by human hands and particularly untouched by

agrarian technologies which had the affect of altering environments in managing them for human purposes.

By considering the indigenous people as part of nature,

Europeans were able to envision an untouched, pristine forest.

This view of the Amazon and its people has dominated

the way that most of us have thought about the region ever since.

It was the view that the American geographer Hamilton Rice brought with him to the Amazon in 1925.

The age of exploration is not yet over.

Great areas still exist awaiting investigation.

Besides being the largest river in the world, the Amazon flows through the greatest forest.

No more savage wilderness exists anywhere on Earth.

In this forest the trees are so thick, the jungle so tangled, the swamp so extensive

that it is impossible to travel except along rivers many times difficult of navigation.

Hamilton Rice set out to map the Amazon wilderness with the latest technologies.

The Hamilton Rice expedition was super well equipped

with a hydroplane to have the aerial views,

and also they had a radio system.

So it was a big, big enterprise.

The new auxiliary method of exploration and surveying,

namely photography from the air, was successfully employed in the exploration of difficult

country for the first time in this expedition along the Rio Negro, the Rio Branco...

I think Hamilton Rice portrayed the Amazon as his American audience want

to see it, as the empty space to be conquered, a space that was easy to put on a map.

You could travel over it, you could dominate it with your technology.

This portrayal of wilderness would have resonated with an American

audience whose own recent history was one of conquering the American West and its Indian peoples.

In this wilderness, usually close to the rivers, live scattered tribes of

Indians eking out a bare existence in a hard and exacting environment.

Rice brought American science and racial ideas to bear

on the indigenous peoples that he came across.

We took anthropological measurements to add to the data that we were gathering to bring back.

It's a very good example of turning the human into natural history.

You know, you took... you measure, you make it...

you know you've got the profile vision, you have the front vision, and create your object of study.

The Indian, put down anywhere by himself in the wilderness, can survive.

His adaptability to his environment is admirably attuned, but any initiative for progress is lacking.

To Hamilton Rice the indigenous peoples were almost like wildlife -

too few and too primitive to make any impact on the pristine vastness that surrounded them.

They were, in effect, irrelevant.

Today archaeologists and anthropologists are challenging this simplistic view.

There is evidence that hunter-gatherer

communities have been living in the Amazon for more than 10,000 years,

but until recently they were considered to have minimal effect on their environment.

Now research on how current hunter-gatherers move about the forest,

creating temporary camps, is revealing something unexpected.

Today's hunter-gatherers in the Amazon are not

passively adapting to the forest, but they are actively managing it.

And, intentionally or unintentionally, they are creating

patches of forest with wild edible plants like palms and tree fruits.

Every time they open a camp they are disturbing the forest and they are

creating a new type of forest that is a more rich forest.

The result is a forest that's rather less virgin than we imagined.

It's an anthropogenic - or man-made - forest,

one that owes its character not just to the interplay of natural forces

but has also been significantly shaped by the people who have lived in it.

Some plants, if you collect them and then throw the seeds away in your garbage, well, then they do better.

And so the fruits are bigger and then you say,

"These are better than the ones over there, so we'll use more of these."

So you're selecting upon the plants that have already been selected by where you threw them away.

And this thing then grows into a tree and is later perhaps distributed by other organisms

that also like the pulp of that fruit tree, and they could then

move into such places and spread the human effect around, but it's still an anthropogenic effect.

Every time they abandon each of these camps, when they return,

most of this forest is not any more a natural forest,

but is like a small garden.

Over a period of years, a hundred years, and over a period

of millennia, this forest that just started with the opening of a camp is going to be a pretty managed forest.

For millennia, hunter-gatherers of one kind or another have been living across the Amazon,

and all this time they've been reshaping a forest we've thought to be pristine.

But surprisingly this idea of a forest shaped by humans is not a new one.

450 years ago the first European explorers to set foot in the Amazon

gave a very different account of the region and its inhabitants.

In 1541 the Spanish conquistador Francisco de Orellana

sailed down the Amazon river in search of El Dorado.

And although he never found the mythical City of Gold,

he left a rich testimony of the wonders he encountered throughout the epic journey.

It's a very important document,

because it's the first written thing that we have by a European

about the Amazon and its people in the early 16th century.

"The further we went, the more thickly populated

"and better did we find the land.

"There were many roads here that enter into the interior of the land,

"very fine highways.

"Inland from the river to a distance of six miles, more or less, there could be seen some very large cities

"that glisten in white and, besides this, the land is as fertile and as normal in appearance as our Spain."

He couldn't believe how gorgeous the culture was.

He raved over the beautiful pottery which the women made,

and the clothing, the beautiful painted robes that people wore, just amazed him.

And they were struck by the enormous biodiversity,

just thriving with life,

thought of as a bountiful paradise, a Garden of Eden.

And indigenous peoples

who they came across found to be very healthy, they appeared to have

a very good diets..

The Spanish there, they went so hungry they had to eat their leather belts.

They were absolutely incapable of fishing or hunting in the forest.

So the admiration they must have had for the Indians who could furnish them a great amount of food.

And they talk about maize, about bread, probably manioc bread.

They talk about fish and turtles and all sorts of nuts and fruits.

Orellana's account was quite literally unique.

No later traveller confirmed what he'd seen.

When you compare the chronicles from the 16th into the 17th century you see something totally different.

A hundred years later,

they all have disappeared. I mean, those large settlements,

they will find just a house or two,

a village or two, things like that.

Where were all the people and all the towns that Orellana had reported seeing?

Could he have concocted a fictitious account

or had something cataclysmic happened?

And there's argument about that.

So was he exaggerating his claims for the Spanish court, or was it accurate?

On his return to Spain, Orellana fell out of favour with the court and as a result his extraordinary

account of the Amazon went unpublished for centuries.

What we do know now, is that in the Amazon, like the rest of South and North America,

the arrival of Europeans like Orellana and subsequent colonists

and missionaries brought catastrophe for the indigenous population.

The people who lived on those places disappeared because of diseases, slavery, warfare.

They were like, you know, the spread of diseases was very, very strong.

Smallpox, the flu, it had a very strong effect on those people.

It is thought that maybe up to 90, 95% of indigenous peoples were actually decimated

by European diseases to which they had very little resistance.

So what Europeans after Orellana saw when they visited the Amazon

was a sparsely-populated region inhabited by the few survivors of these devastating waves of disease.

By the 18th century we begin to see the description of forests, pristine forests.

From that time onwards the idea of the forest that held sway in Europe, America and even in Brazil itself,

was the Amazon as a pristine paradise, empty of people.

And as the 20th Century progressed, this empty land looked ripe for exploitation.

In the 1970s, the military government of Brazil

saw in the vastness of the Amazon an opportunity.

To expand the country's economy and solve the problem of a burgeoning population of landless peasants.

Grand road-building projects were slicing through the forest

to give access for the development of cattle ranches and farms.

It was a very interesting and probably not so good time for the Amazon in the '70s.

There were many different programmes going on to populate the Amazon.

They thought it was a land without people and so they were looking for

people without land in several parts of Brazil and sending these people there.

But even as the trees were being felled, experts were questioning

one of the basic assumptions behind the government's campaign.

That the green forest meant fertile land.

New research was revealing the unexpected nature of the Amazonian soils, and an American archaeologist

called Betty Meggers would use this to redefine the way we think about the Amazon ecosystem.

The soil was very infertile,

so you've got to fertilise it all the time, and then the first rain

washes it out, so it's not a viable situation.

You've got high temperatures, you've had high rainfall and there for many millions of years,

so you've had chemical, leaching chemical weathering

that has long since sort of weathered away and washed away all the valuable minerals and nutrients from the soil.

And on top of that,

you don't tend to get the accumulation of leaf litter

and the organic humus that you find in this part of the world.

Any organic material that falls onto the forest floor is very rapidly

decomposed and recycled and put back into the living material again.

Ends up back in the trees very, very quickly.

And as the deforestation continued regardless, the scientists were proved right.

They cut down all the trees and the next crop was smaller, and then pretty soon the soil was exhausted

and they didn't get anything and everything that's been tried has

demonstrated the non-feasibility of dense sedentary cultivation and so forth.

In other words, the forest may look lush, but it is not fertile,

or as Betty Meggers put it in 1971,

the Amazon was a Counterfeit Paradise.

The idea of a counterfeit paradise, the idea that under that appearance

of abundance of richness of resources lies

a very fragile, frail difficult environment to be managed by people.

In Meggers' view the only kind of agriculture the Amazon could support

was the kind of small scale cultivation, practised by many of today's indigenous population.

It's called slash and burn agriculture and it's a way of farming sustainably on poor soil.

A patch of forest is cleared and the crops are grown until the soil is nearly exhausted.

At the end of three years the fields stop producing so they go cut another one and move around

and have a territory in which they can

maintain a population that's sustainable.

If they get too big a one they end up with people not having enough to eat.

So you would never establish a big settlement for a long period of time

in the same place because you didn't have the resources to maintain that group - that was her first argument.

Betty Meggers subscribed to a mid-twentieth century school of thought

that related the size and complexity of human societies to their environment.

Harsh environments would limit the development of culture.

This theory also said that in the tropics not only could humans not develop as a biological species

but humans could not develop their highest civilisation.

As a counterfeit paradise it was thought that the Amazon never had,

never could and never would sustain big or complex human populations.

This theory added scientific credibility to the notion of pristine forest,

at a time when opposition to the deforestation was mounting.

The destruction of the Amazon became a focus of concern for many different groups and interests.

Some NGOs collaborated with indigenous tribes

and other poor forest communities, trying to protect these people and their lands from developers.

Other NGOs took a more conventional approach to nature conservation,

including some international wildlife conservationists.

Many people characterised

development in the Amazon

as fundamentally bad, human impacts of any kind.

The people who were doing biodiversity conservation were like,

if it flies

or walks on four legs, that's important,

people are bad.

In the '70s the Brazilian government began protecting some of the forest

through the creation of National Parks.

They initially followed the American conservation model.

The old traditional approach to conservation, for National Parks, for

example, has been to put up a fence around a particular plot of forest

and to keep people out and under the assumption that anything kind of human land use is detrimental.

As a result it became illegal for people, both indigenous

and mixed race forest communities, to live in the new parks.

Environmentalism can be a new form of imperialism.

We see that kind of imperialism working at different levels,

on an international level, but also at a local level here in Brazil.

It amazes me today that conservation officials,

they think that it's necessary to exclude

traditional inhabitants,

indigenous people or peasants, caboclos or mestizos from conservation units.

A lot of people, traditional inhabitants, peasants, mixed blood people

have been living in those conservation units for decades

or even centuries, and they have been kicked out now because these places are going to become national parks.

Against a backdrop of environmental concern, the destruction of the forest continued apace.

Then, in a curious twist, the deforestation brought to light evidence that would

challenge the beliefs of environmentalists, archaeologists and even the developers.

In 1986, the Brazilian Geographer Alceu Ranzi was on a flight

to Acre in the southwest Amazon when he spotted something unusual.

And he was sitting at the window seat and he saw this huge structure, very large.

And then he realised that it was not a single site

that probably there were more and so he rented an aeroplane and he started flying around and

then he found more and more and more and then he as a geographer, he knew that it was something very special.

You know that was not natural, that probably was very ancient.

Where trees had been felled strange shapes emerged from what was thought to be virgin forest.

These huge earth structures are known as geoglyphs.

So the geoglyphs are trenches that were excavated in the form of geometric figures.

So mostly we find circles, rectangles and composite figures.

And these trenches were cut very deep, they are today about one or two metres but when we

excavate them we found the ancient depth was three, four or five metres, so that's a lot.

And also their width - it's about 11, 12 metres.

As the deforestation continued, the discoveries kept coming,

and by 1999 Alceu Ranzi had found 30 geoglyphs.

But this was just the tip of the iceberg.

One day they were just you know looking at Google Earth

and somebody saw a geoglyph in a Google Earth.

It was very special for us, because like in two weeks we have found 100

and that never has stopped growing the number of sites we can identify.

They may measure almost the size of two football fields and they show

incredible geometric precision, often the squares and rectangles

have an orientation almost perfectly north south

and this is an uncanny precision because there doesn't seem to be a functional reason for it.

There's no way you're going to do and go through all the effort of

doing something very geometrical if you don't have a reason for that.

I tend to believe that there was a religious reason of some kind,

something that we will probably never know, but still.

What we do know is the extraordinary age of the geoglyphs.

The earliest are 2,000 years old and the latest from about 750 years ago.

This means that for more than a millennium, people were dramatically

shaping an area previously thought to be virgin rainforest.

Today we can find so many sites in Acre, so many geoglyphs

because there's no vegetation and that's something that makes us wonder

what is under the vegetation that's still up in many other places in the Amazon.

Some estimate that what we can see represents only ten per cent of the total.

If proved right, this apparently uninhabited region could have sustained some 600,000 people.

However, the identity of these people remains a mystery.

Besides the geoglyphs, they left practically no traces of themselves.

We know that for sure that lots of people were

necessary to build the geoglyphs, but where have they left their remains?

Where are the burials?

Where are the houses, where are the ceramics? We just don't find them.

But thousands of miles away, on the island of Marajo in the mouth of the Amazon River,

another lost civilisation left a clearer record of their lives.

This is the Pororoca.

A tidal surge that twice a year travels in from the sea.

Its name in the indigenous language translates as the big roar,

and it can be heard 30 minutes before its arrival.

It is the longest wave in the world.

It moves at 35 miles an hour, picking up force as it travels inland.

By the time it hits the river banks the impact is terrifying.

It erodes soils, sweeps away trees, animals and houses.

But that's not all that Marajo puts up with.

There are months of heavy rains.

So for more than half of each year, most of the island is submerged.

The result is a landscape shaped and dominated by water.

To survive here in the past people built earthen mounds

which archaeologists have since rediscovered.

They were built because those are flooded lands.

So people had to build mounds in order to manage that environment

and to have high ground to live on top of it.

But the mounds were more than a safe haven against the floods.

In 1949, while excavating one of these structures,

Betty Meggers found something that no-one expected.

A huge earthenware jar covered with elaborate symbols and harbouring human bones.

It was a funeral urn, part of a burial ground that turned out to contain six more urns.

For Meggers, working with a theory that challenging environments limit the development of human culture,

the elaborate ceramics were a surprise.

We had seen this beautiful pottery and what we wanted to find out was where did it come from

and what was the history and that was what we were trying to find out.

Together with artefacts revealed in further excavations, they showed that a sophisticated

human society, complete with belief systems, hierarchy and symbols, had overcome the harsh environment

and flourished in a land thought to be uninhabitable.

So Marajo was a surprise to them,

because it had very interesting pottery and very sophisticated

ways of making that pottery and that didn't fit the model.

How could a group use complex techniques in a very hostile environment? It didn't fit.

To Meggers it was clear that these people must have come from elsewhere.

And for her, the clue to where they came from lay in the polychrome or highly coloured ceramics.

The people that I worked with have traced the origins back to

Colombia and so forth where you get the earliest polychrome

painting, you get a number of features that are found in Marajoara culture

and burial and all that sort of thing.

She said those people came from outside,

got there with this advanced culture and lived there for 200 years and they disappeared.

According to Meggers, a more sophisticated immigrant

civilisation moved to Marajo, bringing their culture and ceramics,

but then foundered and declined in the harsh conditions of the Amazon.

But a new generation of archaeologists would begin to question this interpretation.

Later, even people who worked with Meggers have got carbon dates

for the occupation in the island.

They found out that the Marajoara culture has lasted for 900 years.

If you cannot survive in an environment that's not good

for human populations, how could they not only stay for 900 years there,

but have those beautiful ceramics

and produce a culture that's comparable to any other in the world?

In fact, Denise Schaan's later research found that the people of

Marajo had been producing ceramics for an even greater period of time,

as far back as 3,000 years ago.

And comparing the earlier and later sites, Schaan showed

that the societies had evolved and not declined.

What had changed at a certain point in time is that they had started building the mounds and they started

just decorating these ceramics and producing ceramics

very distinct in different shapes and doing these funerals and these feasts and things like that.

Clearly complex societies had survived for millennia on Marajo

Island but the question of how they sustained themselves in a region ill-suited to agriculture remained.

Schaan believes she knows the answer to this question and how it relates to the mounds.

I saw the way that people today still today manage, for example, fish in the island.

When the rains stop and the waters start to go down

the fish get trapped in lakes and small streams

and even temporary lakes and then people go there and just they catch the fish.

I mean, it's not fishing you just catch and put the fish in the baskets. It's very easy,

and then I realised that all that was going on very next to the mounds

and in every mound you could find these kind of things.

So it became very clear for me that the mounds were linked to, related to the fish ponds.

The ancient inhabitants of Marajo had used ponds on the edge of their

mounds to intensify fishing and secure a reliable source of protein for most of the year.

It looked like these ancient communities were not passive

survivors at the mercy of their Amazon environment,

but were deliberately reshaping the land and managing the wildlife

in ways that allowed them to develop complex cultures.

This was a radical new idea that challenged conventional

beliefs about the limitations of human development in the Amazon.

Beliefs that would be further shaken by another outstanding discovery in the 1980s.

Not artefacts or earthworks, but the earth itself.

A soil of almost miraculous fertility, known as terra preta or dark earth.

The discovery of terra preta, black earth soils in Amazonia, is a truly amazing discovery,

because Amazonia has always been assumed to be very infertile and not to be conducive

to intensive agriculture.

The soil is almost oily, very dark.

It's almost like working in a coal mine.

And these soils are extremely fertile, and are far more fertile than the surrounding soils.

In fact, the crop yields produced on dark earths are so good,

that it is now widely regarded as the most fertile soil in the world.

Well, the other thing is that these soils are very stable, and

that's what's so fascinating about the terra preta as well, because

one problem with contemporary agriculture in the tropics is that

one has to put a lot of fertilisers,

and very fast, after two or three years, those fertilisers are washed away by the rain.

Terra preta soils they don't lose their nutrients.

They are very stable for over hundreds of years.

And wherever terra preta is found, there is evidence of human occupation, going back centuries,

often in the form of broken ceramics which archaeologists call pot shards.

The amount of pot shards that one sees on the surface,

and also buried on these sites is really, it's huge.

We find evidence of houses, of fences, of structures,

platform mounds for the building of the houses.

We have evidence of food processing on those places as well.

Sometimes we dug cemeteries, people are being buried there.

So to me they represent the ancient settlements of the people who lived in the Amazon in the past.

The most remarkable thing about this miracle soil

is that ancient people didn't just use the terra preta, they created it.

And we know that because in the southern Amazon,

people like the Kuikuro tribe are still creating dark earth today.

So what had seemed impossible had already been done.

Indigenous peoples had transformed the one thing that everyone thought

would have prevented the development of large civilisations in the Amazon.

And there was yet another striking revelation to come from the Dark Earths.

It was to do with accounts left by Orellana in his search for the legendary Cities of Gold.

The very interesting thing is that his description of these cities

stretching over many miles down the main Amazon river,

these cities coincide perfectly with the main distribution of terra preta, black earth soils.

We find terra preta sites in places where he travelled and we find that his description of the pottery,

which he compares with the finest pottery made in Malaga,

really matches the colour and the patterns of the pottery that we find.

Also he talks about palisades, fences around villages and we've dug structures like that.

So I think it's a very good, I think it's very close to reality. He wasn't making that up.

It was becoming clear that the so-called virgin rainforest

had in fact once been home to a substantial population.

And we know through the archaeology that the areas adjacent to the floodplain were full of people.

We have sites from the headwaters of the Amazon to the mouth of the Amazon.

So most people today work with the hypothesis that there were like around 5.5 million people

in the Amazon by the time of the arrival of the Europeans.

450 years after it was written, Orellana's account was finally vindicated.

Far from being a fantastical traveller's tale, it is now widely accepted as historical record.

Most of Orellana's observations were made close to the Amazon river,

but archaeologists are now looking further afield for clues to the rainforest's pre-Columbian past.

In the 1990s, at the heart of the largest indigenous reserve in Amazon,

Michael Heckenberger began to piece together a picture

of the communities that thrived at the time of Orellana's voyage.

What I was really interested in looking at was their deep history.

I wanted to work with them on their oral history and

particularly the archaeology of previous communities extending back hopefully into pre-Colombian time.

And within weeks of arriving in a Kuikuro village, the Kuikuro chief

showed me an ancient archaeological site,

which we now know dates to just about the time Europeans first arrived in the Americas

and was over ten times the size of the Kuikuro village.

Since then, Heckenberger has collaborated with the Kuikuro on a series of archaeological digs

to find out much more about these ancient settlements.

And it was elaborated with earthen structures including ditches

and palisade walls, curbed roads, a large curbed plaza

and an occupation area that extends over 50 hectares.

Over the past couple of decades we've been able to map dozens of sites, many of them that large.

So in the area where I went to live in 1993 with the Kuikuro who were living in one village.

In 1500, there was two dozen villages, many of which were five or ten times as large.

When the ancient earth structures were mapped out, a pattern began to emerge.

The Xinguanos are well known for living around a large circular

plaza, a ring of houses which has a clubhouse in the middle.

That same plaza organisation was the central feature of ancient communities.

They were ten times larger, there was many more people, but that

same kind of circular plaza village orientated the ancient communities.

And when Heckenberger and his team found the remains of ancient roads,

it became clear that these sites indicated something more

than the isolated settlements of today's Amazon.

We mapped archaeological roads with GPS.

Based on that mapping, what we've done is extrapolated

the directions of those roads across the landscape

and to our surprise they actually link up with other archaeological sites

and so the entire region was organised

almost like a lattice work of roads, north to south and east to west.

Sounds very urban.

Heckenberger was revealing a highly-planned pre-Columbian

settlement pattern unlike anything that had existed in the Old World.

They were integrated in these multi-centric clusters.

They always a single central community.

They had two major satellites, one to the south, one to the north,

two other major satellites to the east and west.

And those five communities formed a core area and it's this

multi-centric form of urbanism that's really quite novel.

We haven't seen anything similar to that anywhere else on the planet.

It's an alternative form of urbanism.

But in terms of integration, regional design and planning,

in many respects they were more complex than the Ancient Grecian polis

or the medieval towns and villages.

The next stage was to get an idea of the extent of these settlements across the region.

In doing this, the researchers capitalised

on the fact that the Kuikuro villages are rich in dark earths, terra preta.

In the Xingu what we've seen is that the indigenous population

in settlements, has changed the actual properties of the soil

and that these minute changes in the soil chemistry

actually cause the vegetation to grow differently.

And that, in turn, affects the look of the forest.

It's not a difference that can be seen with the naked eye

but aerial and satellite imagery can reveal this human footprint.

When the researchers expanded his view to take in the whole Xingu Basin,

the extent of the potential human impact on the forest was revealed.

The black dots represent known archaeology site locations

and locations of current human habitation.

The red dots represent areas that have vegetative signatures that match those of known archaeological

sites and thus have a high probability of being archaeological site locations themselves.

Not only were the human settlements much more widespread than previously imagined,

they also had a significant impact on the wildlife of the rainforest.

The plants and animals that colonised the landscape are slightly different in the road areas,

in the settlement areas, in the agricultural areas, and so, to some degree, the forest itself,

as an artefact of past human usage, preserves that lattice-like structure

that was part and parcel of the ancient built environment.

This enduring human effect on the forest vegetation is one more piece

of evidence showing that large parts of the Amazon are anthropogenic.

So how much of this apparently virgin forest has actually been shaped by man?

When sites like the settlements of Xingu are taken together with the land around the geoglyphs,

the mounds of Marajo,

the dark earth sites and many other areas of study,

a startling picture emerges.

The total area of anthropogenic forest is almost twice the size of Spain.

And it's growing all the time with new archaeological discoveries.

The idea of a vast, unbroken, wholly pristine wilderness is now no longer credible,

and, for many, the terms of the debate over the true nature of the Amazon have been entirely changed.

When people think about pristine-ness they're thinking about

something that comes from the past, a very removed, very ancient past,

and it should be preserved for the future, but there's no such thing,

because in the Amazon what we see is that

at least for 11,000 years there's been people living there

and they've been building this relationship with nature,

so what we have to preserve in the Amazon is the outcome, the dynamic

relationship between the people and nature.

Without people there's no such relationship.

We're preserving something else which is not natural any more.

There is a strong political debate that has to be faced in the Amazon today.

There's a true paradigm shift going on in terms of how the Amazon rainforest and its origins are seen.

We can't understand the diversity without taking into account the human factors of the past.

The idea of a natural order that includes people

is one that challenges the way we all think about wild nature.

And it challenges traditional approaches to conservation

which tried to separate humans from the natural world.

And I don't see any contradiction...

Actually I see a complementarity between preservation of nature

and the fact that people can live in this conservation unit.

What I feel is that you need to facilitate people staying

on their land and buffer them from any invasion of people

who may have more technology, more power, more money to bribe people

than they do, and basically help them to continue there as best they can.

That's the kind of reserve I think will be favourable to the future of tropical forests.

But some environmentalists fear that by showing that the forest has been

heavily manipulated by humans in the past,

archaeologists could be giving the green light to modern

developers to do the same, but on a much larger scale.

Does this mean that the area is ripe for clear cutting and large scale mechanised economic development?

Well, no, that is a completely different thing.

It's quite clear that cutting the forest completely down and replacing it with a field of soya beans

is the kind of use that is not consistent with the survival of that habitat.

In fact, what the archaeologists are proposing is a middle way.

One that draws on lessons from the past, from the terra preta,

that would allow indigenous peoples and other forest communities to grow

and flourish in sustainable ways in the future.

You can have societies that are very complex, very traditional,

very large demographically speaking, without necessarily some

of the things we always thought would be really important like intensive agriculture.

They had all other ways to produce food.

If pre-Columbian Amazonians have been able to manage the environment without completely destroying it

and maybe increasing the biodiversity of the environment,

these are the lessons that I think we should take on.

Today the Amazon population is made up of 20 million people from all races and backgrounds.

Amongst them are 400 indigenous groups, struggling to have their voices heard.

Meanwhile, economic pressures and big businesses push for greater exploitation of the area

and environmental groups give dire warnings of the consequences.

The concept of a man-made forest has added a new twist to the debate.

But whatever the future course of the argument,

one thing now seems clear.

The idea of the wholly virgin rainforest has had its day.

The Amazon is the least known world area in terms of its archaeology.

How much of it is anthropogenic?

We don't know.

But we do know enough to say that you can no longer go into

any part of the Amazon and assume that what you're walking into is a pristine tropical forest.

You might be surprised that just under that root

is an Amerindian pot shard.

Subtitles by Red Bee Media Ltd