Between Oceans and Empires Lost Kingdoms of Central America

When Christopher Columbus passed by this part

of Central America in 1502, he found a people bedecked in gold.

Europeans later named this land Costa Rica - the Rich Coast.

'But their initial interest in these lands,

'unlike other parts of Central America, was fleeting.

'And until the turn of the 20th century,

'archaeologists ignored this part of the world too.

'And yet hidden here for centuries was a treasure trove of ancient

'art and a history of powerful, independent societies.

'This was a land of mysterious stone spheres with vast settlements

'spreading deep into tropical valleys,

'and clinging to the slopes of forbidding mountains.

'And in this spectacular, vibrant landscape, amongst volcanoes

'and raging rivers, between oceans and continents, people

'created art and architecture which was astonishing in its complexity.'

Who were these people that Columbus saw,

draped from head to toe in gold?

Why were their elaborate settlements abandoned,

and what did they leave behind?

'My name is Jago Cooper. I'm a specialist in the archaeology

'of the Americas. In this series, I will be exploring the rise

'and fall of forgotten civilisations,

'from the crystal clear seas of the Caribbean,

'to the new world's most impressive pyramids,

'over the smoking volcanoes of Costa Rica,

'and deep underground in the caves of Central Mexico.

'I'll travel in the footsteps of these peoples

'to reveal their secrets, to unearth the astonishing cultures

'that flourished amongst some of the most dramatic landscapes

'in the world.

'And there are few landscapes more dramatic than Costa Rica,

'where 1,000 years ago, forgotten peoples battled against the elements

'to build a string of cities whose remains snake across this land.'

I want to find out the story of these people.

Find out why they rose, flourished,

and fell - and why that story has remained a mystery for centuries.

'Much of Costa Rica's ancient art

'and architecture was rediscovered during the 20th century.

'These discoveries helped us identify dozens of important

'settlements, which had lain buried and forgotten

'for hundreds of years.'

Archaeologists group together southern Costa Rica

and northern Panama under the term "Chiriqui" - a period roughly

800 to 1,500AD, when a collection of powerful societies arise.

A period of religious,

political and population growth that ends as suddenly as it began.

'It's a story that archaeologists are only just beginning

'to piece together.

'And to begin to understand the civilisation of the Chiriqui

'era, we need to understand the landscape in which they lived.'

This land is crushed between two oceans, with the Atlantic

just down there and the Pacific behind.

Just 100 miles between them.

These mountains rise up, with these steep valleys and ridges.

It's a hot, humid, mountainous terrain.

The climate and landscape combine to make this

a challenging environment.

And Costa Rica is home to some of nature's most destructive forces.

We're coming over the Turrialba volcano,

it's absolutely spectacular.

You can see the smoke coming out of the crater,

cos it's still very active, this volcano.

You can understand why, for decades,

historians believed no significant societies could have existed here.

The landscape seemed too hostile, too fractured,

for major settlements to flourish.

Instead, they focused their attention on what lay at either

end of this narrow strip of land.

To the north, you'll find the empires of the Maya,

and to the south, the famous cultures of the Andes.

But it's here, in this narrow isthmus,

hidden away in these valleys beneath the forest canopies,

that we find a whole series of vibrant cities waiting to be explored.

In the centuries before the Spanish conquest,

a complex and connected series of settlements rose in this

part of the world, from central Costa Rica right down to Panama.

They were able to flourish because this terrain

isn't as inhospitable as it appeared to the Europeans.

There's plenty of water, and volcanic ash creates a rich,

fertile soil.

But even once interest was piqued, finding these lost

cities in this landscape can be something of a challenge.

On average, nearly three metres of rain fall every year,

obliterating wooden structures and organic material.

And rain feeds this spectacular tropical vegetation,

which just engulfs anything man-made within a few years.

'But deep in the agricultural heart of the country,

'archaeologist Jeff Frost and his colleagues have spent

'the last two decades working at a site called Rivas.

'It's a site where we discover the first clues

'about how the Chiriqui people lived - and died.'

So, where should we start?

-So this is actually the site?

-This is the site. This is it.

So there's actually people living on it right now, then?

Yes, it looks like they've utilised some of the stone circles here

and built right upon them.

So some of these walls you see here,

these stones are actually parts of the site.

'The modern world may be encroaching on the ancient ruins of Rivas,

'but roughly 700 years after it was abandoned,

'the outline of a settlement is still visible.'

It consists mostly of stone circles ranging from about ten metres

in diameter to about 30 metres in diameter.

This looks like... Is that one there, coming round here?

Yeah, exactly, we're just about to enter one here.

-You can see the other side of it here.

-Mm-hm.

And it circles round this way.

And on that side of it we have one of the other architectural

features, which is a series of steps coming up from a causeway.

And these, they look almost like they are level platforms -

do you think these have been humanly levelled,

or have they just taken advantage of naturally flat ground?

It looks like what was happening here was they were modifying

the natural landscape, so as you move up from one terrace to the next,

these are natural terraces, but what they have done is they have

moved the rocks around into the positions that work for them.

And where are we standing here?

What is this stone platform, do you think, telling us?

This is one of probably about 30 stone circles in this site.

This isn't one of the largest ones, but it's pretty close.

This one's about 20 metres in diameter, and is constructed of

these large boulders that would have been moved into these positions.

This originally would have been a covered space, most likely,

so if we had been standing here in AD 1,000 or so,

we would have been inside one of these large, conical structures.

The evidence suggests that Rivas consisted largely of these

structures - probably homes - for several hundred years.

These families would have harvested maize

and other crops for subsistence.

But Jeff believes that at one particular moment

in the Chiriqui era, Rivas underwent a substantial change.

A collection of homes was transformed into an important

religious site - one which looked very different.

They completely rebuilt the site, and that involved building

the main monumental architecture on this central axis.

The central axis consisted of plazas, these stone circles,

steps, staircases, causeways - all arranged sequentially

in order to move people from one end of the site, through the site,

and then eventually up to the Panteon de la Reina above.

There were probably ceremonial specialists, funerary specialists,

chiefs, priests, all of whom would have helped

control the activities and guide participants through.

This strikes me as really important.

Rivas was completely rebuilt.

Houses were replaced with grand plazas.

And processional roads transformed Rivas from a village

into a place of pilgrimage.

The main road led people to a ridge-top cemetery called

Panteon de la Reina - the "Pantheon of the Queen" -

which was once one of the biggest cemeteries in the region.

'And perhaps one answer to the mystery of this transformation

'can be found in the way that the Chiriqui treated their dead.

'1,000 years ago,

'the processions through Rivas would have ended at gravesites here.'

-There's one right there.

-Where? OK, cool.

-That thing there?

-That's the top of one.

So how would these things have been around the grave,

do you think?

From the best we can tell,

they probably didn't mark individual graves,

but probably groups of graves.

In the way that the cemetery was organised, deceased members

of a single family would have been buried near one another.

So it does appear that they would have commemorated those

individuals and then when they themselves died

they would have been buried with their deceased family members.

'The bodies buried here are long gone, devoured by the tropical soil.

'And sadly, human hands have emptied the graves of valuable artefacts,

'vital clues to Chiriqui life.'

You can see, if you look around here, all these marks in the soil

are looted graves, or at least places where

looters thought there were graves.

So you can define the boundaries of these cemeteries pretty accurately,

by just defining where these holes are.

'But we can guess what the looters were looking for - gold.'

It is said that there were literally pounds

and pounds of gold coming out of this site every day for months.

So the looters would have systematically gone through

here, trying to find the graves, digging them up, tunnelling

to the ones on either side of it and then just taking out the gold.

Heartbreaking though it is to lose

so much of the treasure of Rivas, it's not surprising.

Today, gold is the ultimate symbol of wealth and power.

And because they placed so much gold in their ancestors' graves, perhaps

it held a similar significance for the Chiriqui people.

They certainly used it as an emblem of authority among certain figures.

We know that chiefs often had large amounts of gold.

Other high-status individuals, elites,

would have worn lots of gold.

Probably many commoners didn't have access to gold, so it was

one of those ways of defining who was in charge and who wasn't.

'The gold in these sites gives us some clues about the structure

'of Chiriqui society, but there are so many questions to answer.

'What intrigues me most about this hidden world at Rivas is

'the sudden change that occurs here - the unexplained metamorphosis

'from a residential settlement

'to what appears to be a place of pilgrimage.

'It was a major change in how the Chiriquis

'organised their settlement,

'which in turn would have changed the way they lived their lives.

'Walking around the site helps me to visualise the landscape,

'understand the lives of the people who were living here.'

There's a lot more going on in this part of the world

than was thought for a long time.

What's behind this rapid change at Rivas around 900 AD?

And what's the motivation behind this big phase of construction?

Is the answer connected to the large amounts of gold coming

out of the cemetery at the top of the hill?

The Museo Nacional in San Jose holds many of Costa Rica's

pre-Columbian artefacts.

'I've come here to talk to Myrna Rojas, who manages the collections,

'to find out if these objects can help explain

'what happened at Rivas.

'There is, of course, a lot of gold in the stores here.

'But, intriguingly,

'there are also artefacts from a different source - jade.'

TRANSLATION:

These pieces of jewellery are made from jadeite -

a form of the gemstone jade.

Evidence suggests that, before gold,

jade was the precious material of choice for people in this region.

These beautiful depictions of animals, birds and gods

represented agriculture, vitality, the power of life itself.

We haven't found a major source of jadeite in Costa Rica.

But we do know it was mined in modern-day Guatemala,

over 500 miles to the north.

And we know the use of jadeite flourished in the Mayan empire.

This is a surprisingly important fact.

If the Chiriqui were importing jade from the societies to the north,

they were also forming other connections -

probably trading not only goods, but also ideas and customs.

So, whilst jade was being used, the Chiqirui were clearly in contact

and exchanging influences with their northern neighbours.

But around 700 AD,

something strange happened in Costa Rica - people stopped using jade,

and started using gold.

The earthiness of the jade was replaced by a fine,

delicate gold-work which I've seen many times before, not to the north,

but to the south, over 600 miles away in the Andes.

These little shamanic figurines hint at a developing religious

culture different from that of the jade artefacts.

They suggest that religious faith is bound up not just with

the spiritual, but also with the physical well-being of the Chiriqui.

We saw that in the graves above Rivas,

gold was associated with power.

And it's likely that gold was controlled, and worn,

by the leaders of that society.

So gold had a political role and a religious role, conferring

both status in the community, and religious connections.

The transition from jade to gold is critical to

understanding how the Chiriqui world changed.

If the presence of jade signified influence from the North, then the

growing importance of gold suggests that influences had now shifted.

Which brings us back to our theme of connections,

because as the jade starts to disappear here,

we know that to the north,

the great Mayan city states were in a state of decline.

So, is it the case that as trade routes to the north are disrupted,

people here looked south, where the dominant cultures valued gold?

And, if they did, what does that tell us

about the lives of the people of the Chiriqui golden era?

'How would the change of attention from North to South change them?

'How did they live? And what did they believe in?'

In 1872, the forerunner of the American United Fruit Company

built a railway line connecting coastal ports to the interior,

in order to get its banana crop to market.

But during construction of the railway, one of the workers

found some unusual objects hidden in the undergrowth.

'Purely by accident, the country's biggest banana exporter had

'stumbled upon a lost city even more important than Rivas.

'The clue was 30 beautiful pieces of gold.

'Today, the once-lost settlement of Las Mercedes is

'managed by the EARTH University...'

HE SPEAKS SPANISH

'..and has been extensively

'studied by Ricardo Vazquez of the National Museum.'

So this is the cut coming through one of the buildings?

This is... exactly, one of the buildings,

and this is the cut of a tramway for bananas.

And this is the expanse of the site looking out over the...

Right. Exactly.

We are at the northern most part of the architectural court.

Yeah, if you look at the relief of the site, there are quite

a lot of mounds.

There is one over there, there is one over here.

So how far do these mounds spread out?

-It's about 11 hectares.

-Wow.

-The architectural court entails 11 hectares.

-That's massive.

'Las Mercedes offers us an opportunity to confirm the theory

'that a change in influences helped start the transformation at Rivas.

'And it does just that.

'It appears that, like Rivas, Las Mercedes underwent big

'changes shortly after the decline of the jade trade.'

The monumental architecture that we can see now

started at around 900 AD and continues all

the way for about three or four centuries. Only around 7.5%

of the site is occupied by what we call group areas.

I mean, features that qualify as households.

In which case, when we think about this site, we're not just

thinking about a big town full of residential complexes.

We're thinking about a space which brings together people from the

region at different times to meet, and what are they doing when they come here?

One thing we know is that now we are finding some gathering places

like plazas that are integrated into the administrative complex.

These plazas are really interesting because they are also paved.

That means they've got quite a bit of people getting into the plazas.

Las Mercedes looks like it was an important settlement, where

people congregated to celebrate important events.

'And, although looting has occurred here too, thousands of artefacts

'have been recovered from the site, and the surrounding area.'

What type of artefacts are coming out?

Well, gold, jade artefacts. Ceramic artefacts.

But perhaps the most impressive types of artefacts

are the stonework and the beautiful statues.

Some of them human size.

In other words, the site was filled with public sculptures.

I mean, sculptures that were decorating the site.

What do you think these artefacts tell us about what type

of site it is? If you imagine walking through this vegetation,

you've got these big stone sculptures you walk through -

what does that say about the people who were living here,

the type of site it was?

Right, I mean, it looks like they were trying to impress people,

the people who came into the site,

and not only with the sculptures but also with the architecture, and they

wanted to create that psychological impression to the visitors.

Next to the plazas, where hundreds of people would once have gathered,

was the biggest house in the settlement.

This was the house of the chief,

and was at the heart of public life in Las Mercedes.

This is the area that we think is the very heart

of the administrative centre.

That area over there used to be where the main mound was placed

and the whole thing relates to observations done by the

Spaniards, where the Spaniards say the house of the chief was

a very high house - the main house -

and also that was his office.

That was his administrative quarters.

And right beside it there was another similar house that

was for his family, where his sons, daughters, wives, were living.

Even centuries after it was abandoned, you can still feel

that this was the centre of Las Mercedes.

Many of the grandest statues were found scattered around here.

And there are tantalisingly ambiguous hints at just how

dramatic a spot this would have been.

There's a depression in here, in this nice, circular,

semi-circular wall running round.

What do you think the role of this depression in front of that

-mound would have been?

-We started with two hypotheses.

The first one was a sunken plaza that was paved,

and that's why it's so wet.

And the second one is that it was a reflecting pool.

Now, we are leaning more towards the second hypothesis, that it was

a reflecting pool, because all around the area is a pavement that

slopes down into the plaza. That means that it was collecting

water, rain water, and bringing it to the plaza.

And then this is really interesting,

because it will reflect what was the main house, in a way.

Visually, it would have been very dominating,

if you have this big house structure on top of this big mound

and you're walking and approaching it through a reflecting pool.

The whole thing, the whole vista, would have been quite dramatic.

To me, it's really clear

that the site was dominated by the political figure.

I'm getting a sense of how these settlements were organised.

It's not just the gold, or the statues,

it's the way the people have manipulated the landscape itself,

creating a reflecting pool outside the chief's house to emphasise

the importance of the dwelling, and of the individual inside.

The intention was to leave no-one in any doubt the chief was at the

centre of political power here, and that implies religious power too.

'But something else strikes me -

'the plazas suggest Las Mercedes was designed to be seen - to be visited

'by people from the surrounding valleys and further afield.

'This meant people came here to visit.

'And, at the edge of the site, Ricardo and his team

'have discovered how these visitors were drawn in.'

-So, underneath here is the road, then?

-Yes.

-Nice.

This is the very end of one of the two roads leading to Las Mercedes.

And how long does the road go -

if Mercedes is... How far down the road is Mercedes?

It's 1,700 metres from here exactly,

according to the map.

This seemingly random jumble of boulders was once a road

seven metres wide, meticulously constructed using

thousands of stones extracted from nearby rivers.

They're almost like procession ways between sites.

So when you get close to a site, you start to walk along it,

and you have a sense of drama and arrival?

That's exactly what we think they are.

That's the function they had.

But also they are just formalised entrances to the site.

They were for controlling access to the site.

These roads were hacked out of the forest across this region.

They would have been used to connect settlements which otherwise

would have been cut off from one another by the tropical landscape.

And a grand causeway like this,

emerging from the forest as people approached Las Mercedes,

signifies just how important it was.

The implications of this road are profound,

because it requires hard labour - labour that needs to be

controlled and co-ordinated by someone - a political hierarchy.

And the purpose of these roads is to connect both practically

and ideologically communities together, which suggests trade,

interaction, a linked network of sites, sites similar or perhaps

larger than Las Mercedes, hidden somewhere in these valleys.

But to find those other communities in this landscape

is difficult and arduous.

Sometimes, a river works better than a road.

It's coming to remote valleys like this that you remember

just how extreme this part of the world can be.

It's a land full of environmental hazards - earthquakes,

volcanoes, floods and landslides.

But it's that ability to control the environment, harness its power,

that takes great skill, and it's key to understanding

how the cities emerged here.

'The natural world played a central role in pre-Colombian life.

'In order to flourish, cities had to be built in harmony

'with the landscape, hugging the contours of hills,

'guarding against the destructive power of fire and water.'

Water is key to understanding the landscapes here in Costa Rica.

It cascades down from the steep volcanic slopes

and funnels through raging rivers like this one.

It's what makes the landscape so lush and provides so much food.

But it is also dangerous. Floods are common,

and they can wash away villages and settlements in an instant.

'But as well as providing fertile territory,

'the rivers serve another purpose.

'River networks connect people,

'and so were critical to trade and communication for the Chiriqui.'

It's no coincidence that many settlements

were built where rivers met.

And here, between two rivers and on the slopes of an active volcano,

we find our largest settlement yet.

It is the greatest example of these peoples' ability

to harness their tough natural environment.

This is Guayabo de Turrialba,

a site which once housed several thousand inhabitants

and likely dominated life in these lush valleys 1,000 years ago.

Archaeologists have uncovered only a portion of this site.

Much of it still lies under the forest.

But what we can see is a highly developed, highly organised,

and powerful settlement, which thrived for hundreds of years.

Since controlled excavations began here in the 1960s,

archaeologists have uncovered dozens of mounds.

Just like the stone circles of Rivas,

these would have been the foundations of large homes.

And as at Rivas and Las Mercedes, there's more than homes.

In this case wide plazas, roads,

and even functioning aqueducts have been discovered.

Guayabo is the clearest example of just how impressive settlements

in Costa Rica had become in the centuries before Europeans arrived.

Mauricio Murillo has studied and written about Guayabo's history.

He believes that here, again, the most significant architecture

was completed in a short burst at the end of the first millennium.

There's a genius to this architecture.

Guayabo lies over 1,000 metres above sea level,

on the slopes of the Turrialba volcano.

It is drenched by three metres of rain every year.

And yet the people who built it were able to use this unpromising

natural environment to their advantage.

As well as guarding against flooding,

the people who built Guayabo

harnessed the natural flow of water through the landscape.

As the clouds broke on the volcano above,

rainwater was captured by a series of aqueducts and then directed

into communal tanks for drinking, bathing, and ritual purposes.

Everything in Guayabo is on a bigger scale compared to what

I have seen so far, but the similarities are clear.

This road stretches deep into the forest, just like at Las Mercedes.

You can see how it controlled access to the site,

funnelling people into the centre -

a central highway like the one at Rivas

which led religious processions up to the Panteon de la Reina.

And the construction of such a complex settlement

suggests a significant level of political control.

A chief would have been the most important political figure

in the community, standing at the top of an elite group of citizens,

and commanding the loyalty and labour of people for miles around.

But it wasn't just political control that the chief commanded.

'We can see a design that suggests the chief controlled nature itself,

'from the fiery volcano above to the running water below.'

In the middle of this plaza is a striking stone-built mound.

This would have been the residence of the chief, and on top

would have been a wooden structure, with a conical, thatched roof.

What I really like about the mound

is that it makes the most of the landscape.

The entrance procession would have led up here, and you would

have seen this chief's house framed by the Turrialba volcano behind.

It really gives a sense of power

and dominance of the landscape to the chief within.

And like at Las Mercedes, water appears to have been funnelled

'into these shallow pools in front of this residence.

'It would have been an awesome sight for any visitor to Guayabo.

'The wide road led them directly to this spot.

'In front of them the chief's house, reflected in a large pool of water.'

Behind the house, the fiery volcano,

the most potent force in the natural world.

Human construction and the natural world combined to emphasise

the power of the chief and their allies.

'At all three sites I've visited,

'there has been a rapid transformation

'at around the time jade ran out, and gold started to dominate.'

We can't say that gold alone explains the changes.

But I'm convinced it is part of the answer.

'It makes me wonder what other developments

'are associated with gold.'

All the sites I've visited in Costa Rica so far seem to have undergone

significant change around about the same time,

at the end of the first millennium AD.

And this usually involved a period of expansion and growth.

Politically, it's a picture of cities being controlled by chiefs,

and religion always plays a key part at each site.

This period of dramatic growth always seems to be associated

with the arrival of gold and if that's the case then the next

question has to be, where did the gold come from?

For centuries, prospectors have headed to southern Costa Rica

to pan for gold in the rivers which empty into the Pacific Ocean.

More than 90% of the gold in San Jose's museums

comes from that part of the country.

And that's where I'm heading now.

Occasionally gold nuggets as big as eggs have been washed out

'of the rivers and streams which crisscross southern Costa Rica,'

making this area a great source of gold.

'And making it an important bridge between Costa Rica

'and cultures to the south.' Woo-hoo!

Archaeologists believe people from the south,

who already worshipped gold, sailed up the Pacific Coast

in search of new sources, and to trade with the people here.

And one of the most important trading posts

was at the mouth of the Diquis Delta on the Isla del Cano.

This island was a trading post for gold.

But that culture of gold didn't spontaneously emerge here.

It developed with influences from further afield -

almost certainly from down that coast,

where great gold working cultures of South America were emerging.

'Just as jade is associated with connections to the north,

'so gold signifies a connection with the south.'

Gold was central to the people of the Andes.

To them, it was much more than a simple metal.

Gold objects were associated with political power

and spiritual authority.

So in societies where control over gold was limited to a select few,

these individuals wielded huge power over the community.

Is this what happened here?

The emergence of powerful chiefs

who ruled thanks to their control of gold?

Chiefs who could command large scale building projects

and the expansion of settlements.

On this island where the two worlds met, the gold is long gone.

But there are hints that an important society

did once exist here.

These are some of the stone spheres of the Diquis Delta.

Nearly 300 of them have been found

and production peaked during the Chiriqui era.

These spheres aren't created on a whim.

They are found throughout the region.

What role did they play in the lives of the people who lived here?

They must mean something. The question is, what?

There are many outlandish theories about them -

that they are aligned with Stonehenge, with Easter Island,

even that they were part of the lost city of Atlantis.

All of which, we can safely say, are nonsense.

'But whatever their purpose,

'the effort that went into their creation is remarkable.'

This has been carved from an igneous rock

where the outcrops are on the mainland,

transported over 12 miles out to this island.

It tells us something about how significant these pieces

of monumental architecture are to the society that they are being

transported across the landscape and placed in places like this.

Today, these spheres are everywhere in southern Costa Rica.

In parks, in schools, even in people's gardens.

They have become a national symbol.

And once again, we have the humble banana

to thank for inadvertently uncovering Costa Rica's past.

We've seen how the people here tried to live in harmony

with the landscape, building roads, settlements.

But not all the people who came here were so careful.

Some, like the United Fruit Company,

have radically altered the landscape.

In the 1930s, they came here and took down the large rainforest that

covered southern Costa Rica and put in huge banana plantations instead.

But during the process of the constructions of the plantations,

they discovered hundreds of stone spheres

that had lain hidden for over 400 years.

'The National Museum's Francisco Corrales

'is in charge of excavating one of these old banana plantations.'

Finca 6 is the centre of the sphere-making culture in Costa Rica.

The spheres were created using simple hammers.

These would be used to batter and chip away at massive rocks

until they were almost perfectly spherical.

'Some have a smooth, polished finished,

'achieved by rubbing sand across the surface.'

Centuries of rain and flooding have covered this site in deep layers

of sediment, leaving much of what was once here barely visible today.

But Francisco and his colleagues believe there is much more

to be discovered beneath these banana plants.

This site could be even bigger than Guayabo - a huge settlement

which may well have dominated this landscape 1,000 years ago.

And although the spheres are unique to the south,

the society that created them

sounds similar to the settlements I've visited further north.

'Societies in which rank was important.

'In which political and religious power were concentrated

'in the hands of a few significant individuals.'

The spheres are mainly found in southern Costa Rica.

They aren't found in Rivas, Guayabo, or Las Mercedes.

That shows that these settlements were independent of one another,

each with its own distinct culture.

And yet the similarities are clear.

Here, as further north, the chief and their allies used impressive

architecture like roads and statues to emphasise their power.

And at Finca 6 you can get an idea of just how powerful

the local chief was when you consider the effort required

to build his city of spheres.

It's a two-hour horse ride deep into the Talamanca Mountains,

to the spot where archaeologists now believe

the spheres began their life.

This sphere was not meant to remain here.

It was abandoned unfinished.

It was hewn out of one of the massive boulders

which cover this forest, making this place a quarry.

'And if this is the quarry, then moving these spheres into place

'must have been a truly enormous task.'

In between here and the valley below are rivers, ravines,

and steep slopes covered in dense vegetation.

So moving spheres like this, many weighing several tonnes,

down to the valley can only have been achieved

by a highly organised and obedient society.

This has profound implications for our understanding

of the way of life of the indigenous peoples in Costa Rica.

The spheres demonstrated power.

'Firstly, the power over nature to make them, and secondly,

'the power required to physically move them across the landscape.

'And all of this revolves around the power of the chief,

'who was able to command this incredible production'

and who would have the biggest

and most impressive spheres placed outside their house.

Looking at this sphere I can't help but see a complex, inventive,

and significant society behind it.

Just like Rivas, Guayabo, Rivas, and Las Mercedes,

there is an explosion in building and art around the same time,

when gold becomes the dominant material in the region.

And the way people live becomes more hierarchical,

centred on rank, status, and power.

But when the Europeans arrived,

they did not find a harmonious, prosperous people.

They found a world at war.

In the 16th century, Spanish accounts of brutal

indigenous warfare in this part of the world were common.

'One account describes roads piled high

'with hundreds of severed human heads.

'And that is the great unsolved questions

'of the Chiriqui era in Costa Rica.

'What happened? What caused this warfare?'

And why, when the Spanish arrived at the start of the 16th century,

did they find so many of these settlements

in decline or abandoned altogether?

One clue could lie deep in the Southern Costa Rican mountains.

After the arrival of the Spanish we know that the indigenous people

retreated here to the remote Talamanca mountains

next to the modern-day border with Panama.

And whilst we cannot identify the direct descendants of the people

of the Chiriqui era, we know that these indigenous populations

have managed to hold on to their beliefs,

customs and practices for hundreds of years.

The people who live here today are known as the Bribri.

15,000 live in scattered communities along the Panamanian border.

For many years they have existed on the fringes -

a reminder of Costa Rica's pre-Columbian past

'but not quite part of its modern story.'

'Meyor Leandro is a local Bribri community leader.

'Like a shaman of old,

'he is responsible for the health of the people who live here.

'And today, he has invited me into his surgery.'

So, the baby is seven months old, called Asley,

and the mother has brought her here cos she's been poorly.

And now Meyer Leandro is starting to prepare some of the plants

to try to and improve and solve the problem.

So, Meyor Leandro is toasting these leaves and then brushing them

over Asley, the little baby.

I don't understand how this treatment is helping little Asley

but Leandro's attitude to the causes of illness

is one that has existed amongst the Bribri for hundreds of years.

There's an interesting concept about where illnesses come from.

They are described as being strangers from far away and when

they visit the body they bring with them the sickness and the vomiting.

So, a big part of this ceremony is about purification to get rid

of that stranger and send them far away from the village.

If people believe disease is brought to the village from outside

then two things can occur.

Either you break off contact with your neighbours,

sending your community into isolation and decline,

or you retaliate against the attack.

So, could this have been the cause of the conflict the Spanish saw?

Leandro blames the Spanish for bringing disease

and discord to this world.

There is another possibility.

That the very success of the Chiriqui era

sowed the seeds of its own downfall.

As the people became more adept at mastering

their tropical environment, populations rose

and resources, once bountiful, became scarce...

..leading to conflict.

We don't have enough information to say for sure.

But whether we blame competition for resources or disease,

we can say one thing for certain.

Connections had nourished trade and ideas and sustained growth.

When the connections fractured, these societies fell.

So by the time the Spanish fought their way inland,

the great settlements were already in decline or had been abandoned.

All that was left was their gold.

The people here had thrived by reaching out to the communities

in the north and to the south but those links are broken.

For the first time the Chiriqui people

and their neighbours become isolated.

With isolation comes insecurity.

And with insecurity comes conflict.

Four centuries of rain and the suffocating spread

of tropical vegetation obscured the legacy of the Chiriqui era.

Only now are their substantial achievements coming back into view.

The cities of this era were controlled by chiefs

who built powerful networks far beyond these valleys.

These people shared ideas and traded peaceably

with one another for hundreds of years.

Gold was critical to growth and change

and we have started to uncover

some of the spectacular remains of their vibrant societies.

We know much more than we did just a few decades ago

about this incredible land that was once

relatively unexplored archeologically.

Now we know the people of the Chiriqui era,

how they thrived through their connections

between empires and between oceans.

How they harnessed the power of one of the wildest

and most challenging environments in the world.

And how they produced some of the most unusual, beautiful,

and impressive art and engineering feats in the Americas.