♪ ♪ ♪ ♪ NARRATOR: Rapa Nui.

Also known as Easter Island.

This tiny little island in the South Pacific is world-famous for one thing.

The moai.

Moais are incredible.

The moai is the first part that people see.

NARRATOR: These enigmatic stone giants stand like sentinels all around the island.

But what was their purpose?

And why have so many fallen?

It is easy to imagine that this is the scene of some catastrophe where things fell apart.

NARRATOR: For centuries, Western researchers have studied the moai, trying to answer these questions, and they've come up with their own theories.

But now, new research that looks beyond the moai is challenging those views.

TERRY HUNT: In all the evidence that we saw, we were seeing signs of sustainability.

There was really no evidence of collapse.

NARRATOR: And Rapa Nui experts are reclaiming their heritage.

HETEREKI HUKE: For you, this can be an ancient, abandoned village.

For me, it's the place where my family used to live.

NARRATOR: Genetics is revealing surprising clues about the origins of the island's earliest settlers.

ALEX IOANNIDIS: When we first saw this, we thought maybe we did something wrong.

NARRATOR: From their incredible engineering to their beautiful and unique writing... HUKE: Some people say that they contain legends.

NARRATOR: ...the real story of Rapa Nui is finally coming to light.

"Easter Island Origins."

Right now, on "NOVA."

♪ ♪ ♪ ♪ NARRATOR: Most visitors come all the way to Easter Island because of these stone statues: the moai.

HUKE: Moais-- they are amazing and they're outstanding.

And they are unique.

♪ ♪ NARRATOR: Constructed between 1300 and some time after the 1700s, there are more than 1,000 of these giant carved figures scattered across the landscape.

Cut from volcanic rock, some are more than 30 feet high.

Over time, all of the moai have fallen down.

The 50 or so that are upright today were put back up in recent decades.

With their backs to the sea, they stare impassively into the island, arms held rigidly by their sides.

Some stand on ceremonial platforms known as ahu.

Others are sunk into the earth.

But for the people who live on Rapa Nui, Easter Island's true name, the moai are just the beginning.

HETEREKI HUKE: Moais are incredible.

But Rapa Nui is so much more than that.

And its archaeology is so much richer than just moais.

The moai is the first part that people see, but behind the moais there is a big history.

(translated): Everywhere you walk, you can find the remains of the past.

And that's why for us everything is always important, not just the moai.

(translated): Our connection with each of the archaeological sites has a direct connection with family.

It's not a legend, it's not a myth, it's not a made-up story or something discovered by archaeologists.

It is something that belongs to us.

♪ ♪ NARRATOR: One archaeologist who believes the story of Rapa Nui encompasses more than just the moai is Sonia Haoa Cardinali.

Born on Rapa Nui 70 years ago, she has dedicated her entire life to the history and anthropology of the island.

SONIA HAOA CARDINALI: I feel sorry when they just talking about the moai.

70 percent of the island is surveyed, more than 25,000 archaeological site.

So that's means not only the sites, it's mean also how people live, whats they do, the family, and everything.

NARRATOR: Sonia wants to understand more about the moai, but she and other Rapanui islanders see them as only part of the puzzle.

There are bigger questions to ask.

Who are the ancestors of the Rapanui people?

Where did they come from?

And how did they survive and thrive in this remote and hostile land?

♪ ♪ (birds chirping) The island of Rapa Nui stands alone.

♪ ♪ The easternmost inhabited rock of the Polynesian island chains, it lies approximately 2,000 miles from the Tuamotu Archipelago of French Polynesia in the west, and Chile in the east, 4,500 miles from Hawaii.

Only 14 miles long by seven miles wide, today most of the roughly 8,000 inhabitants live beneath an extinct volcano on the western corner of the island.

♪ ♪ First encountered by the Dutch in 1722, it was claimed by the Spanish nearly 50 years later; then annexed by Chile in 1888.

But when the original Rapanui people first came to this land, and where from, remains hotly debated.

The general consensus is that the first people to settle here were sailors from other Polynesian islands, migrating east sometime around 1200 CE.

We are Polynesians.

Our life was the canoe, and our territory was the ocean.

Polynesians, we were populating and colonizing islands across the Pacific.

♪ ♪ NARRATOR: That belief forms the heart of Rapanui identity, cherished by Elders like Carlos Edmunds.

(translated): In ancient legends it is said that in the month of October, the Rapanui went out to sail their boats to new lands.

(translated): I am not surprised by anything, we're great sailors and that is how we arrived to the island.

NARRATOR: It is the bedrock of Rapanui oral tradition.

HUKE: There's knowledge in the old people, in the oral history.

Behind every legend, there's knowledge there.

NARRATOR: Legends handed down from generation to generation tell how and why their ancestors came to this land.

They are retold even today by Rapanui performers dedicated to keeping the old traditions alive.

(man speaking Rapanui) STORYTELLER (translated): Haumaka went into a spirit dream looking for a new land for the king, till he found the navel of the world.

(speaking Rapanui) (translated): He tells the dream to the king, who summons seven scouts and sends them in the direction of the dream.

To find and explore the island.

(man speaking Rapanui) (translated): Hotu Matu'a and his wife follow in a ship called Haua Iki Nui.

(speaking Rapanui) (translated): The scouts call down to him saying, "Turn back!

"Turn back!

This is a bad land.

The weather changes all the time and our crops cannot grow here."

Hotu Matu'a replies, "We came from a bad land "where the ocean kills the people with great waves.

Let's make this a good land for our people."

(speaking Rapanui) That is the base of all our history.

Fortunately today, science and scientists are helping us to show how oral tradition was the first, the most, and the real history.

NARRATOR: That oral tradition reflects a deep and fundamental truth.

For settlers migrating from the warm, tropical islands of Western Polynesia, this windswept lump of inactive volcanoes in the southeastern Pacific was a "bad land" where their crops could not grow.

Rapa Nui is a subtropical island.

So there's a big difference in climate to the tropical islands, for example, of French Polynesia.

The problem was that some of those tropical species just didn't grow and didn't take.

NARRATOR: Because it's colder here, the first settlers of Rapa Nui, traveling from the Polynesian tropics, would have struggled to grow any plants they'd brought with them.

♪ ♪ One man who is fascinated by how those settlers survived on this "bad land" is Hetereki Huke.

You know what, there's not that much material... NARRATOR: An architect by trade, Hete started an office in 2014 to record Rapa Nui's heritage through the archaeological record.

At that moment, there were not many young researchers in Rapa Nui.

They're releasing the... (indistinct chatter) NARRATOR: So Hete turned to Terry Hunt and Carl Lipo from the U.S.A. HUKE: We have been collaborating with Carl and Terry for a long time, and we have done so many things together.

They were a great support during these fieldworks.

And that was amazing, because with Carl and Terry we could map the rocks and at the same time, we could have the legend behind them.

And that, that is just beautiful.

NARRATOR: One of the sites they studied was Ahu Tepeu, which lies on the northwestern coast of the island and was a typical ancient Rapanui settlement.

Central to its layout is the ahu, a raised stone platform.

At Ahu Tepeu, there are five of these.

HUKE: Some of them with moais, and some others without.

NARRATOR: Fanning out from the ahu are the houses, chicken coops and walled gardens known as manavai.

And behind the houses lie the fields that fed the community.

HUKE: For you, this this can be an ancient, abandoned village.

For me, it's the place where my family used to live, and they still are here.

This place is quite alive for us.

So the approach of a Rapanui researcher, or any Pacific researcher, would be dramatically different from a Western researcher.

NARRATOR: Rapanui and Western researchers agree that the ancient settlers were Polynesian-- but where did those Pacific Islanders come from?

Some previous research suggested that they came from the islands of East Asia.

But in 1947, a Norwegian explorer named Thor Heyerdahl launched an expedition called Kon-Tiki, intended to prove a drastically different view of where the Polynesians originated.

(man speaking French) (translated): Thor Heyerdahl proposed the idea that the Polynesians actually originated in South America.

To demonstrate this, he managed to build a boat, or raft, made of balsa, a South American wood.

He made the crossing on this raft in a few weeks, landing on the Tuamotu Archipelago, which is now in French Polynesia.

NARRATOR: His theory on South American origins flew in the face of known linguistic evidence.

So Heyerdahl followed this up with a series of archaeological expeditions to Rapa Nui.

But despite years of investigating the island, he could never prove a definite link to South America.

One Rapa Nui archaeologist who worked with him was Sonia Haoa Cardinali.

CARDINALI: I worked with Thor Heyerdahl for almost ten years and for me it's an honor to work with him.

No matter how we think about his theory, never forget that he's the one of the person put Rapa Nui in the map.

NARRATOR: In Heyerdahl's day, experimental archaeology seemed the only way to explore possible links between Polynesia and South America.

But today we can use DNA-- which is a powerful tool for tracing human ancestry.

So did the original settlers of Rapa Nui have links with South America?

One geneticist who set out to answer that question was Andrés Moreno Estrada.

ANDRES MORENO ESTRADA: Genetics can be a powerful tool to answer this big question about whether the Rapanui people made contact or not with Native Americans in pre-history, which has been a debate that has been on for decades.

NARRATOR: Andres put together an international team, including researchers from Hawaii and Rapa Nui, to study the DNA of the people of Polynesia.

And they reached out to the community to gain the support of Rapa Nui's elders.

ESTRADA: Community engagement is really the essence of all these approaches.

When you study human genetic diversity, it's all about humans, really.

It's a voluntary participation, so it's really key to talk with the community beforehand.

And as we carry out the research as well, keep them informed about the results of the study.

NARRATOR: Collaborating with Andrés is genetic data analyst Alex Ioannidis.

IOANNIDIS: What I really love about genetics is it's essentially about participation with the people whose story you're telling.

It's their sample that's telling the story.

NARRATOR: Stories like Bianca's-- the daughter of a Chilean father-- who moved back from mainland Chile and wanted to know if what her mother had told her was true.

(translated): When I arrived here on the island, everyone told me I was Chilean.

I was a mongrel.

So that's why I did the study, because my mother taught us our genealogy.

CARLOS EDMUNDS: (speaking Rapanui) (translated): I am happy that Andrés came to do this work about the blood of the Rapanui, where we descend from, so that the Rapanui know where their current ancestors are from.

TUKI (translated): Andrés suggested we do the study to know if we really have ancestry from Polynesia.

PONT IKA (translated): It's absolutely important, since our ancestors know they are Polynesian, but if there is a study that confirms it, it's even more important.

♪ ♪ NARRATOR: An individual's DNA is contained within 23 pairs of chromosomes, known as a genome.

IOANNIDIS: And that's your genetic fingerprint.

NARRATOR: When they began their research, Andres and his colleagues were expecting the Rapanui fingerprint to contain markers showing mostly Polynesian, Spanish, and Chilean ancestry, since these were the main colonists of the island in the last 250 years.

To extract the DNA, they take swabs from their volunteers in the field, then take it back to the lab in cold storage, for analysis.

MORENO-ESTRADA: DNA samples are loaded into a sequencer so that we can get the pieces of DNA that make up the whole genome of that individual.

NARRATOR: This allows the researchers to identify specific chains of DNA that can be attributed to certain groups.

Red denotes Spanish ancestry; blue, Polynesian; green, Chilean... and yellow, other European.

MORENO-ESTRADA: The process is very rewarding because participants are very interested in knowing about their own genetic origins.

And when they see they actually they have retained a lot of the Polynesian roots in their DNA, it's something that helps them to basically value and identify their own lineages.

NARRATOR: Most of the results helped confirm the islanders' beliefs about their Polynesian origins mixed with more recent colonists.

ALVARO ATON: I just found out the results.

I'm so mixed; my mom is from Chile and from England, and Scotland.

And my father is an islander, but he's also mixed with French and other people.

So it's very interesting to know where you come from.

(speaking Spanish) (translated): I'm very, very, very happy.

Because this is my mother's story, and this study from Andrés proved it scientifically.

But my mother already said it a long, long, long time ago, since I was born.

NARRATOR: They did, however, find some pieces of DNA that they didn't expect.

IOANNIDIS: When we first saw this, we were really surprised, and so we thought maybe we did something wrong.

MORENO-ESTRADA: We thought, "Well, let's double check this."

NARRATOR: These pieces of DNA seemed to have their origins in South America.

But when they tried to pinpoint the source, they got a surprise.

They were quite different from the more modern Chilean ancestry found in some volunteers.

We compared it to a panel of indigenous groups from across the entire Pacific coast of South America and the closest match was the Zenú group.

♪ ♪ NARRATOR: The Zenú are a Native American people who occupied the coast of Colombia, long before Chile annexed Rapa Nui in 1888.

How could their genetic markers wind up in the DNA of modern Polynesians?

And how many generations back did they go?

Because each parent only hands down half of its DNA to the next, Alex was able to figure out when that piece of pre-Colombian DNA had been incorporated into Polynesian chromosomes, by measuring its length.

IOANNIDIS: We can actually look at the length of those individual pieces and figure out how many generations ago this combination of Native Americans and Polynesians took place.

NARRATOR: The date they came up with was much earlier than they expected.

IOANNIDIS: We saw very small pieces indicating that this ancestry from the coast of Colombia entered Rapa Nui a long time ago, actually in a period around what we would call the European Middle Ages, around 1200 A.D. NARRATOR: What's more, the same identical DNA segments were often seen in volunteers from different islands.

IOANNIDIS: Which means that these segments came from the same ancestors.

And since they came from the same ancestors, we think that this means there was a single contact event between indigenous Americans from the coast of Colombia and Polynesians.

MORENO-ESTRADA: This means that a group of Polynesians met, somewhere, with Native Americans, had descendants, and more likely, this never happened again.

NARRATOR: By looking at the DNA of people on other Polynesian islands, the team traced the tell-tale genetic markers back to the Marquesas and Tuamotu Isles.

And were also able to plot a timeline of migration across Eastern Polynesia to Rapa Nui from around 1100.

IOANNIDIS: Polynesian migrations spread east into Tuamotu Archipelago up to the Marquesas and all the way down to Mangareva, and from there all the way out to Rapa Nui around 1200.

NARRATOR: Looking closely at these particular islands, there's something else they all have in common-- something much bigger than DNA.

IOANNIDIS: Most of these islands-- the Marquesas, Rapa Nui, and Raivavae, have these very large stone statues on them.

Where the idea of creating large stone statues comes from, we can't say, and we can't say for sure if these islands developed the idea independently, but the fact that they're all existing together in the same genetic cluster suggested to us that this culture was developed once and spread to all these islands.

NARRATOR: Sonia believes that even if this culture developed within the Polynesian islands, there was also some influence from South America.

And behind the spectacular Ahu of Tongariki, she believes she has the evidence to back up her hunch.

We see there very good evidence of influence of South America.

NARRATOR: This single broken moai has its hands across its body in a style that can be found in ancient Colombia.

♪ ♪ CARDINALI: If you compare with the South America, it's the same.

The hands and the description of the arms, the body.

it's completely the same.

There is no doubt the influence of South America.

In here, we have the structural evidence.

I cannot lie you, that is, that is look like a moai normal.

No.

(chuckles) No, maybe if I am blind, yes.

But, it's there.

NARRATOR: But this is the only moai on the island with arms across its body.

All others have their arms by their sides.

So it cannot prove that the template for carving statues in stone came from ancient Colombia, though the DNA suggests some ancient, albeit isolated, link.

What is provable is where the moai were created.

Almost all of the statues scattered around the island were carved from the volcanic rock of Rano Raraku.

And on the slopes of its massive crater, about 400 statues can still be found in various states of completion.

High up on these slopes, Carl and Terry can see evidence of the skill and ingenuity of the Rapanui stonemasons.

TERRY HUNT: It's amazing being up this high in the quarry and all the work and quarrying out of the bedrock and statues this big that way up here had to be taken down the slope.

You can see several moai being carved.

The large moai here, and there you can see the beginnings of moai up on the side as well, high up here in the quarry.

CARL LIPO: Yeah, what we're seeing is the aggregate of events that occurred... HUNT: Yeah.

LIPO: ...over 500 years of activity here at the quarry, not a final product.

This is all the things that happened here.

It's interesting because the quarry, it's kind of a common area that's shared.

And so there's an understanding that everyone on the island, every community on the island has access to the resource here.

NARRATOR: But rock isn't just confined to the quarry.

All over Rapa Nui, rock is spread across the land.

To Western explorers like Captain James Cook, who visited the island in 1774, this looked like a wilderness.

JAMES COOK (re-enactment): "The ground had but a barren appearance, being a dry hard clay, and everywhere covered with stones."

HUNT: The early European visitors saw crops being grown in stones, and they thought this was somehow pathetic because they're expecting to see ploughed fields and the agriculture of Europe.

NARRATOR: How could the Rapanui survive on what appeared to be such a barren wilderness?

But this wasn't what it seemed.

HUNT: The soils on Rapa Nui are nutrient poor.

There is an ingenious solution to that, and it's using rock mulch.

NARRATOR: Volcanic rock is packed full of nutrients that bring new life into the world.

Somehow the ancient Rapanui had learned how to make the best of this austere landscape by fertilizing their fields with stones.

HUNT: And using rocks in cultivation will release nutrients into the soil and make them available to the plants.

NARRATOR: Sonia also sees lots of evidence that the rock-strewn wilderness described by Captain Cook was actually fertile fields.

Here you see a very nice complex.

And that's mean you have everything here.

In the center part, you can see they take all the rocks, and what you see in, in the landscape around here, it's like a garden, yeah?

♪ ♪ NARRATOR: This was not the first or last time that Western misconceptions would color the history of Rapa Nui.

Right from their very first encounter on April 5, 1722, the world-view of its European visitors would have a profound effect on the island.

The name Easter Island comes from the first Europeans arriving here on Easter Sunday.

The modern traditional name is Rapa Nui, and the older traditional name is Te Pito o Te Henua, which really means "the navel of the world," which probably reflects the island's isolation and-or its centrality as the whole world.

♪ ♪ NARRATOR: The first encounter between the Dutch explorers and the local residents was marked by curiosity and a tragic misunderstanding.

KÜHLEM: There was a lot of interest in, in the landing party.

There was a lot of interest in the construction of the ships.

People swam out to the ships.

They went aboard.

They measured every aspect of the ships.

And the landing party was quite substantial.

(man shouting) NARRATOR: The Dutch landing party found themselves confronted by a vibrantly painted man.

HUNT: He performs what they perceive as a very strange dance.

And this strange dance was probably really an important ritual that the Rapanui would have perceived as proper in these people coming ashore to their land.

He saw the possessions that the Dutch had-- the clothes, the hats, and the guns.

And he reached for the gun... (man speaking Rapanui) KÜHLEM: And several crewmen opened fire.

(gunshots firing) So the very first encounter on the shores of Rapa Nui was overshadowed by 12 islanders dead and many more injured.

CAUWE: (speaking French) (translated): This story is a case of misunderstanding, a clash of cultures.

The islander is curious and wants to know what the soldier has in his hands.

He wants to hold it, feel it.

Meanwhile, the soldier is afraid he is trying to steal the gun and puts up a fight.

This is a clash of two completely different worlds.

NARRATOR: The clash of cultures that led to this massacre would profoundly affect the way that Rapa Nui was perceived by Western researchers in the centuries to come.

HUNT: Western preconceptions have colored the view of Rapa Nui in many ways.

Seeing the moai, seeing the monuments here, they can't imagine how, uh, people would move them, with no wooden carts or wheels.

And because they don't understand how it could have been done, it leads to notions of the mystery of Easter Island.

And the mystery is really just what visitors didn't understand.

♪ ♪ NARRATOR: Just as with Captain Cook, Western visitors saw a barren land, covered in rocks, and devoid of the trees needed to make wooden sleds or wheels.

But it wasn't always like this.

Researchers found pollen evidence in the fossil record, suggesting that 1,000 years ago, much of this land was covered in dense forest.

(translated): One millennium later, the forests have vanished.

So, we have to ask the question: what happened?

(bird chirping) ♪ ♪ NARRATOR: For many Western researchers, the answer lay strewn across the island at sites like Ahu Tepeu.

LIPO: These are pieces of moai, the large statues that once stood on top of the ahu.

I don't know how many statues there were here, maybe four or five.

And it's easy to look at these landscapes-- when you see the ahu, when they're broken down, and statues that are fallen and broken like this one here, which has no head and just the body, the head that's over here-- to imagine that this is the scene of some catastrophe where things fell apart.

NARRATOR: To Western eyes, this was evidence of a collapse of society.

So successive generations of Western scholars constructed a narrative.

It explained the barren, rock-strewn land, the collapse of the moai, and the disappearance of the trees.

LIPO: The collapse story basically goes that people got to an island that was filled with trees, palm trees, other kinds of trees as well.

Sort of an earthly paradise filled with food and opportunities for, for the people that were here.

The moai building has often been portrayed as some kind of frenzy, as some kind of competition between different clan groups, where lots of trees were cut down in order to construct and to transport the moai.

NARRATOR: Archaeologists had long investigated stone monument building in places like ancient Egypt.

Westerners thought the moai were probably moved on wooden sleds or rollers pulled by hundreds of men, which required people and trees-- lots of people and trees.

And these Westerners assumed that moai building had spiraled out of control.

People here kind of got into a moai mania that they started to make bigger and bigger statues.

And at some point, that overexuberance of statue construction ultimately depleted the island of the resources needed to make up ahu in the first place.

NARRATOR: According to this view, moai building deforested the island.

The soil was starved of nutrients, leaving a barren, rock-strewn land.

Then, this theory goes, things got worse.

KÜHLEM: The scarcity of resources resulted in a societal collapse.

The island erupted into inter-tribal warfare and led to a very impoverished population living on a barren island.

(translated): And the best evidence to prove this was that all the statues had been thrown to the ground.

So something violent must have happened.

And the one visible proof we have today is all the statues that were toppled during these "wars."

♪ ♪ NARRATOR: This so-called collapse theory posited that the island once had more than 10,000 inhabitants, whose own folly triggered a collapse of the forest ecosystem and reduced them to a mere 3,000, living on the scraps.

For many Western scholars, it was a compelling narrative, a morality tale for our times.

But for some researchers, this idea had one big problem.

LIPO: When we looked at the evidence on the ground, we simply didn't see evidence of warfare.

It looks like this one is being dismantled, because we find some of these construction elements in the other features over there.

NARRATOR: For Hete, what were once considered ruins at Ahu Tepeu turn out to be evidence of continuous use.

HUKE: This is the head of a moai that was part of the second ahu in this ceremonial complex.

In the second ahu, all of the moais lay down in the back of the platform.

And that is because that second ahu was being dismantled to enlarge the first one.

NARRATOR: Pieces of earlier moai were being reused to create an even more spectacular ahu.

HUKE: From this particular ahu, we couldn't say that there's evidence of collapse.

There's evidence of transformation and human societies changing.

And that's beautiful.

Destruction is recycling and creation.

It's part of a larger process.

And in a certain way, this moai reflects that.

♪ ♪ NARRATOR: Across the island, what some Western researchers had seen as evidence of collapse didn't stand up to scrutiny.

Even the island's caves, long seen as refuges against an enemy tribe, appear to be something very different.

LIPO: This is a great example of a cave that has that construction where they've taken a cave and added these features to it.

HUNT: Yeah.

It's not a, it's not a refuge cave.

It's not a hiding place.

It's a habitation.

So they made this nice entrance with paving stones and everything.

LIPO: They've used lots of different materials like this paenga stone.

NARRATOR: Paenga are a kind of foundation stone found in elite houses.

The holes bored into them acted as bases for the wooden struts.

The use of these paenga in cave walls was argued to be evidence of some last-ditch defense against attack.

HUNT: Some people think that this is evidence of tearing down, uh, elaborate or elite houses, and, and reusing the stone out of desperation.

But these stones are reused everywhere.

LIPO: We see the reuse of these paenga stones not only in things like ahu, but also in the chicken houses, the hare moa, as well as earth ovens.

So they're really used in all kinds of contexts.

People use the stone that was available to them, and some of that stone were paenga.

Reusing and recycling stone materials here is really the norm.

NARRATOR: At another set of caves nearby, Hete, Carl, and Terry find yet more evidence of a thriving community.

Here, the Rapanui even used the collapsed lava tubes as hothouses... ...fed by something rare on an island of permeable volcanic rock: an abundant supply of water in caverns deep within the caves.

HUKE: In those caves, we can find fresh water.

It was one of the largest water reservoirs.

So, it's a very rich part of the island.

NARRATOR: So Rapa Nui's caves weren't just simple refuges.

They were complex, sun-dappled ecosystems that had been used for centuries, long before the collapse that was supposed to have driven people into them.

HUKE: Nothing here in Te Pahu or in the area that we worked shows that people were struggling.

On the contrary, they were thriving.

We were seeing signs of sustainability.

There was really no evidence of collapse.

♪ ♪ NARRATOR: Even though Carl and Terry found no direct evidence for collapse, they would not dismiss the idea without more research.

Especially when it came to the population of the island over time.

They started by mapping all the moai on one side of the island.

Then moved onto the settlement and resource sites.

LIPO: Our goal is really to sort of characterize the settlement systems and how people are distributed across the landscape and use resources there.

We've got a good sample of the communities, but we're continuing to do that as an ongoing basis.

NARRATOR: They matched these with carbon dates from the sites to build up a pattern showing when each settlement was in use.

Then they ran them through a computer model, which converted the carbon data into population numbers, by calculating the highs and lows of human activity on the island.

The results confirmed their hunch.

It showed the population rise from a small number of first settlers, continuing to grow steadily, with no sign of collapse at any point.

HUNT: The population could fluctuate slightly, but its average maximum is probably around 3,000.

Probably what Europeans encountered when they first arrived on the island.

NARRATOR: A maximum population of 3,000 was much smaller than the numbers cited in the Western collapse story.

HUNT: The collapse theory proposed all kinds of numbers: 7,000, 10,000, 15,000, even up to 30,000 population for this small island.

NARRATOR: But Carl, Terry, and their colleagues found no evidence that there were ever that many people living on Rapa Nui.

LIPO: The lack of huge populations being on the island sort of takes the wind out of the collapse theory.

Because, in fact, there's nothing from which to collapse.

There isn't a large population.

NARRATOR: But if you don't have tens of thousands of people living on the island, how could the Rapanui build and transport the moai?

For some Western researchers, Rapanui oral history suggested an answer.

(man speaking Rapanui) STORYTELLER (translated): There are many stories about Tu'u ko Iho.

Some people say he was in charge of the second boat that brought people here.

Others believe that he was the great king who founded the island.

But all agree that it was he who made the moai kavakava walk.

(man speaking Rapanui) NARRATOR: This actually referred to small wooden statues.

But some Westerners thought it also described the stone moai.

Thor Heyerdahl and his colleagues attempted to move the statues upright, to effectively make them walk.

But the experiment hadn't worked, so most experts still believed that they were dragged on their backs.

But when Carl and Terry analyzed the moai lying by the roads that led from the quarry, they noticed something significant.

These are impressive things, aren't they?

HUNT: We're looking right here at the reason why they were not transported on logs on their backs.

That's true.

How would they be in this position, face down and the neck broken?

Yeah.

It makes no sense.

That just simply doesn't happen if they're on their backs on rollers.

NARRATOR: They also noticed a structural difference between moai lying on the road and those standing on the ahu.

A moai on the ahu has a flat base, so the statue stands straight up.

But most of the moai lying on the road have angled bases.

And Carl and Terry believe that angle had a very specific purpose.

LIPO: Road moai has to be shaped in a way that can be transported.

They did it by shaping their base so they leaned forward.

It enabled them to walk.

HUNT: This is a great example of, of the forward lean of these transport moai.

LIPO: So if you took the statue, and we could put it back up, it would be leaning really far forward.

It means that as you rock it side to side, it falls forward across that front edge... Yeah.

...and takes a step.

Yeah.

Without that, it would just rock back and forth and not really go anywhere.

And walking really describes what these moai did.

NARRATOR: To test their theory, in 2012 Carl and Terry built a model of a moai out of concrete, carefully mixed to match the fragile density of the ancient statues' volcanic rock and made it walk.

(crowd chanting "heave ho") LIPO: In our experiments, we found it took remarkably few people to move the statue.

And we were terrible at it, you know?

We were the least expert of any people who've ever moved a moai in the world.

Uh, but we were able to do a five-ton statue with 18 people.

NARRATOR: Not all are convinced that the moai walked.

♪ ♪ But if they did, trees were not needed to move the moai.

And the Rapanui continued to erect moai long after the trees had died out.

So why did the Rapanui go to such lengths to build them in the first place?

What were the moai for?

(birds chirping) One tradition that might one day tell us the answer is being lovingly preserved by Luis Huki, a park ranger on Rapa Nui.

LUIS HUKI HINOJOSA: (speaking Spanish) (translated): My name is Luis of the Huki clan.

At the moment, I'm carving rongorongo, which is the tradition of our forefathers, of my father.

And right now, I'm following their tradition.

I've been making rongorongo tablets for 25 years.

I like it because it's a tradition that at a certain time, the translation was lost, and now we must conserve it and continue to make the rongorongo.

NARRATOR: Rongorongo is the traditional writing system of the Rapanui.

It is inscribed onto wooden tablets.

HINOJOSA: (speaking Spanish) (translated): The process starts with preparing the wood and sanding it.

Once it's sanded, the wood is traced so you can start to draw on it.

And then, after that, you carve the rongorongo.

NARRATOR: Luis is one of just a handful of people still carving rongorongo.

He's doing this to help preserve his culture.

(translated): It's unique, and if we lose it, we lose part of the history of Rapa Nui.

NARRATOR: No one knows how old rongorongo is, or what it actually says.

But in a secluded monastery in Rome, Silvia Ferrara is studying a remarkable wooden artifact which might help answer those questions.

This is the Échancrée tablet.

It's made of wood, and it's one of the 27 tablets written in this script, which is still undeciphered.

NARRATOR: The Échancrée tablet was gifted to the Bishop of Tahiti in 1869 by Catholic converts from Rapa Nui.

It is one of only 27 scattered across museums around the world.

And the way its figures are oriented suggests a very unusual reading method.

What you need to do is turn the tablet from one line to the next in order to read it.

And this is a unique feature of this writing system.

No other script works in the same way all over the world.

So it's really quite special.

NARRATOR: Despite this unique system, it has been said that rongorongo was inspired by European writing.

That's kind of a degrading view of Rapanui ingenuity.

It's not only simplistic, but it's patronizing.

It's one of the most unique and beautiful forms of knowledge of art in the world.

Nevertheless, we have to face critics, or thoughts that we were copying.

HUNT: The glyphs in rongorongo are clearly connected to the art on the island.

You see the glyph forms in petroglyphs, They don't imitate European writing in any sense.

NARRATOR: To put the debate to bed once and for all, Silvia gained permission to radiocarbon date this tablet.

FERRARA: The radiocarbon date points in the direction of a 15th-century date, which antecedes the arrival of the Europeans by more than 200 years.

NARRATOR: Silvia believes this might make rongorongo one of the few instances of independently invented writing in the world.

But what was rongorongo for?

Many believe that it contains the secrets of Rapanui culture.

HUKE: Some people say that they contain legends or rhythms or encrypted instructions of how to move moai, or develop some technologies.

There are many, many different theories about it.

But what we do know is that they contain knowledge.

♪ ♪ NARRATOR: Until rongorongo surrenders its secrets, researchers are using tried and tested scientific methods to understand why the moai and the ahu platforms are located where they are.

HUNT: When we, we look at the question of where ahu are located, why are they located there?

Why are some of them very large and some of them smaller?

Why are there some ahu in the interior, while most of them are on the shoreline?

LIPO: It's easy to describe it as being religious.

Certainly, that's part of the story.

But the question is why would you invest so much energy in doing these over and over again?

NARRATOR: They started with a map.

They marked out the locations of all the ahu on the east side of the island.

Then they began to compare them with the locations of vital resources.

They chose three as the key sources of sustenance: rock mulch, seafood, and fresh water.

But when they tried to map the ahu over the rock mulches, a simple mismatch became glaringly obvious.

LIPO: There's rock mulch everywhere across the island, but we don't see ahu and moai everywhere.

What we find is, in fact, that ahu and moai are in particular locations, independent of the, of the mulch itself.

NARRATOR: Next, they looked at resources from the sea.

LIPO: When you drive around the island, you see one after the other, an ahu with moai, all the way along the coast.

And, of course, the coast has a lot of resources.

Fish, shellfish, other kinds of things that would support populations.

NARRATOR: But while the ahu on the coast match sea resources very well, this cannot explain the ahu erected in the interior of the island.

That left one final resource: fresh water.

Most of the moai are along the coastline, with their backs to the sea.

At first glance, that doesn't seem like a good place to find fresh water.

But look a little closer.

The water's fresh.

You think this water's salty, that it's seawater, but in fact, this is a freshwater seep, a source of water that comes from the interior of the island, moves to the underground, and then comes out at the coast.

It's a place where Rapanui people access water for their daily lives.

HUNT: On a young volcanic island like Rapa Nui, the rocks are very porous.

The rainwater will enter the island and flow through the porous island and into lava tubes, etc., and will come down to the level and float on top of saltwater and then enter the ocean at low tide.

LIPO: When Captain Cook arrived on the island, what he saw was people drinking straight from the ocean.

And he thought, "This is crazy, why would people do that?"

What he was actually seeing is people drinking water that comes from these freshwater seeps that emerge right at the coast of the island.

NARRATOR: And when Carl and Terry compared their map of ahu moai with a map of freshwater sources, they got a roughly 90 percent match.

HUNT: In fact, the locations of freshwater are the best predictor of the locations of ahu throughout the island.

NARRATOR: For many, this near-perfect match is not surprising, because ahu are usually linked with settlements.

KÜHLEM: Those hamlets or villages are located, in many cases, close to water sources, which makes perfect sense that the essentials for survival, like your crops and your drinking water, is close to where the people actually settle.

NARRATOR: Yet for Carl and Terry, it's the precise location of the moai that is the key to this theory.

LIPO: One of the interesting aspects about Rapanui people is that they lived in a dispersed settlement pattern in which people used the landscape around the ahu in sort of a wide area.

But they're brought together at the ahu and the moai.

NARRATOR: Again and again, the ahu-- not the settlements-- are closest to the water.

LIPO: So we find, in fact, the ahu and the moai right next to the critical resource because, in fact, that is the heart of the community.

♪ ♪ NARRATOR: It seems the moai acted as a statement, erected close to a community's most vital resource.

But Rapanui tradition would see this differently.

HUKE: They represent the soul of a dead king.

So moais, their location and eventual collapse, is also related with an evolution of our political and social structure.

The statement is "We're honoring our ancestors."

And they might even say to us, if we could time travel, "Don't you honor your ancestors in this way?"

♪ ♪ NARRATOR: Looking at all the archaeological evidence, it seems more likely that, rather than a self-inflicted ecocide, the true collapse of Rapa Nui society was caused by outside influences.

HUNT: As time went on, and the evidence accumulated, we realized that a lot of what people thought was collapse was something that actually happened after Europeans arrived.

And it had an entirely different cause, and that was the introduction of Old World disease.

HUKE: There was the smallpox, there was the Spanish Flu, leprosy, slave trading.

It was difficult to live here, and it was more difficult to keep the social structures and the life as the way that we knew it.

LIPO: Over time, we see people sort of abandoning ahu and moai.

It's a loss of population.

There's just fewer people because of the effects of diseases.

So people are not attending to the ahu and rebuilding them in the way that they did in the past.

NARRATOR: Things got even worse in the 1860s.

KÜHLEM: Peruvian slave traders captured about a third of the population on the island and forced them onto their ships to work in Peru.

(translated): There were protests.

Even the Vatican got involved.

And consequently, the companies were forced to return the inhabitants to the islands.

However, these people had contracted smallpox on the American continent.

Only 15 people made it home, and this was enough for an epidemic of smallpox to break out there.

(speaking French) NARRATOR: By the time it was over, there were less than 200 Rapanui left alive.

♪ ♪ The true story of Rapa Nui is one of survival against the odds by an ingenious and resilient people who came to a "bad land" and made it good.

But that story has been overshadowed by a Western fascination with the moai.

And for Sonia and Hete, that is the true tragedy and triumph of Rapa Nui.

CARDINALI: If we look only the moai, we are not making this place bigger.

We're making it small.

This mean you don't believe in my capacity as a human being.

HUKE: If there's one thing that I would like people to take from Rapa Nui, it's that the history has been narrated by a very selected group of people.

There are different realities.

The world is full of beautiful, amazing stories that deserve to be told, and people deserve to hear.

Our history is not unique.

We share with many islands, and we share a beautiful past, a complex present, and many, many tragedies in the midway.

♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪