Original subtitles

A forgotten city hidden in the heart of South America.

Massive stone slabs

that may possess incredible healing powers.

And a giant sculpture that could rewrite history.

Scattered all over the world

lie a countless number of ruins left behind

by ancient civilizations.

These impressive temples, monuments and structures

are a testament to the ingenuity of our ancestors

and raise some fascinating questions.

How were these remarkable sites constructed?

Why were they abandoned?

And perhaps most intriguingly,

could some of these mysterious places have served

a secret purpose?

Well, that is what we'll try and find out.

♪ ♪

While conducting research high in the Andes Mountains,

archaeologist Dr. Ruth Shady notices

a number of mounds and hills in the landscape

that do not appear to have been made by Mother Nature.

PAUL BAHN: Most people had assumed that these great mounds were natural.

But nevertheless,

when Ruth Shady arrived at the site in 1994,

she realized that there was something here

that was more than just natural hills.

She had an instinct, really, a gut feeling, I think,

which many archaeologists acquire,

that this place was worth exploring.

And, boy, she explored it and hit the jackpot.

SHATNER: As they began excavating,

Dr. Shady and her team discovered the ruins

of a forgotten ancient city

that has become known as Caral.

FELICIA BEARDSLEY: Ruth Shady has spent

years now working in Caral.

Caral has, under her supervision,

become part of the world heritage list now.

So, that says this is one of those unique places

that tells a story about

civilization in the New World.

SHATNER: According to experts, what is remarkable about Caral

is that, unlike other ancient ruins located in Peru,

such as Machu Picchu,

Sacsayhuamán

and Ollantaytambo,

Caral was not built by the Incas.

It was built by a previously unknown civilization

that remains shrouded in mystery.

Caral is one of the most impressive

and most important sites in South America.

Certainly in terms of its size.

Excavations revealed that it covers a huge area,

and was clearly a great metropolis

for prehistoric South America.

You've got this incredible complex

covering hundreds of acres,

with an amphitheater,

supplementary temples,

all kinds of artifacts

suggesting a sophisticated civilization.

BEARDSLEY: The greater pyramid in Caral--

this is the biggest structure there is.

It dominates the landscape.

It is the center of the city.

It is nearly 500 feet long,

nearly 400 feet wide,

60 feet tall,

and on one side of it,

it has this 30-foot-wide staircase

that descends from the very top

down to a sunken, circular plaza.

The whole structure itself

has a stepped profile,

which has a number of very large terraces

built into the side.

There's a network of ceremonial rooms,

some large rooms, some smaller rooms,

built with stone and mortar.

It's a phenomenal structure.

BAHN: This was a culture with no wheels,

with no metal tools.

And so, the building

took an awful lot of people carrying

earthen stones from wherever they got them from.

You needed architects of some kind, maybe engineers.

Probably thousands and thousands of man hours to erect that.

BEARDSLEY: The other thing that shows up

in the greater pyramid that tells us

something about the nature of

Caral as a civilization

are symbols of monkeys.

So, in this part of Peru,

there are no monkeys.

Those actually come from the Amazon basin.

Which means that the people of Caral

had to, basically,

go over the Andes

and into another part

of South America altogether.

So, why is this significant?

It tells us that they are a central point

for a vast trading network.

And not just goods but ideas.

SHATNER: The discovery of Caral's ruins

challenged everything we knew

or thought we knew

about the history of civilization

in Central and South America.

And not just because of its elaborate design

but also because of what experts learned

when they were able to begin carbon dating its artifacts.

BAHN: Towards the bottom of the great mound,

they found remains of what seemed to be

reed bags or baskets

in which the earthen stones would have been carried

to make the mound. These are called shicras.

Of course, you can date reeds by the radiocarbon method.

And so, samples were sent off to various labs,

and to everyone's surprise, the answer was far earlier

than anybody had expected.

The dates came back

to approximately 2600 BC and earlier.

The same age as the pyramids in Egypt,

much older than other civilizations

that were known at the time in the New World.

BAHN: It's very likely

that Caral goes back at least

to that kind of period.

It is arguable that Caral

is the kind of mother culture

for what came later in South America,

like the Inca civilization.

However, there are lower layers at Caral, which have been dug.

They may well find

samples that can be dated

far earlier than anybody expected.

Possibly at a period even several centuries

before the pyramids of Giza,

which will alter our view of the past.

SHATNER: Is it possible

that the ruins of Caral are actually older

than the Egyptian pyramids,

which were built almost 5,000 years ago?

It's an extraordinary possibility,

and the discoveries at Caral are forcing archeologists

to redefine the time line of human history.

BEARDSLEY: What was the old definition of civilization?

It was extracted from the site of Mesopotamia,

which is in Iraq, basically.

Mesopotamia starts at 3500 BC.

and then the idea was that all civilizations

used Mesopotamia as the model.

But looking at Caral,

we expect that Caral is gonna reach back to 3200 BC,

which indicates an incredible possibility

that faces the world of archaeology.

So we have to start rethinking

what we mean by "civilization."

SHATNER: It's astonishing to realize that,

before uncovering Caral,

archaeologists were completely oblivious

to the existence of this vast, ancient civilization

in South America.

But even ruins that are more familiar to us

can still offer plenty of surprises.

For instance, archaeologists have discovered that Stonehenge,

one of the most recognizable ancient structures on Earth,

may have actually been a place of healing.

SHATNER: Experts working in the Acoustics Research Centre

at the University of Salford

publish the results of a groundbreaking study

on one of the most iconic ancient monuments in the world:

Stonehenge.

In their experiment, the scientists constructed

a scale model 1/12 the actual size of Stonehenge,

used speakers to shoot sound waves throughout the model

and measured how sounds reverberated

through the miniature structure.

Their conclusion?

The massive blocks of Stonehenge were designed

to amplify sound.

COLLINS: Everybody knows about Stonehenge.

This is the most famous megalithic monument

anywhere in the world.

But who created this?

Why would they have done it?

What research is now beginning to suggest

is that one of the possibilities

is to enhance the generation of sound used in ritual.

SHATNER: The idea that Stonehenge was used

to amplify sounds made during rituals

is intriguing, but it is just the latest

in a long line of theories about this mysterious structure.

After centuries of study and speculation,

Stonehenge continues to inspire both fascination

and intense debate as to how and why it was built.

HUGH NEWMAN: Stonehenge is the most magnificent stone circle

in the British Isles.

It's unique, it's unlike any stone circle

anywhere on the planet.

It has lintels above it, it's perfectly circular.

And it really stands out as the kind of symbol

of ancient Britain.

People are kind of obsessed by it because

it's the only way they can get back

to have some contact with their ancestors.

SHATNER: Believed to be constructed in 3000 BC,

Stonehenge has stood on the plains of Wiltshire, England

for at least 5,000 years.

With an outer ring of 30 four-ton stones

surrounding five huge arches

whose massive blocks weigh 25 tons each,

Stonehenge's construction

defies explanation.

Such a project could not have been achieved haphazardly.

LYNN PICKNETT: We know that some of the stones

were actually imported from South Wales

which was something like 120 miles away.

A bit tricky

when you don't have flatbed trucks

or decent roads.

NEWMAN: Some of the stones at Stonehenge weigh

between 50 and 70 tons.

So how could you have moved them from Wales

to construct Stonehenge?

These are answers that have

not been properly dealt with.

PICKNETT: For part of the journey, it's been worked out

that they would have floated them on boats.

But then there would be quite a bit of land

to drag them across.

And presumably they used

greased rollers and an awful lot of manpower.

But, again, we don't know.

Once people have actually got the stones to the site

at Stonehenge, the next major problem

is how do you lift them up in the air?

And the only way I can think that you would do that

is that you would make a ramp and you would

drag them up the ramp,

and then tip them off the end.

That's a massive undertaking, so we're talking about

thousands of people involved creating Stonehenge.

And these people are working a 150 miles apart.

Just imagine how complex those logistics are.

We may never really know how they did it.

SHATNER: As if transporting, hoisting

and precisely balancing those giant stones

wasn't incredible enough,

scholars have observed that Stonehenge's

entrance aligns perfectly

with the rising sun on the summer solstice.

The longest day of the year.

COLLINS: It was almost like a marriage

of heaven and Earth together

to get closer to heaven.

And this seemed to be bringing down

the influence of the sky world

on Earth itself.

NEWMAN: It does seem that they wanted to influence

and integrate the natural energies of the Earth.

And these massive, megalithic boulders

with cosmic energies from above

to create this enchanted space

where people could have ceremony.

SHATNER: Were Stonehenge's megalithic boulders

intended to be energetically linked

to the power of the sun in some way?

It's a certainly a thought-provoking question.

And it might help to explain yet another mystery.

The burial sites that are all around Stonehenge--

you can see hundreds of burial mounds.

The kind of people that are buried there

come from all over Europe.

In other words, they were visitors there.

It was a site that people were coming to from all over Europe.

Now, why were they coming there?

What's strange is that the archaeology suggests

that many of these people

had some long-term illness or disability

suggesting that they were going

to Stonehenge in the hope of a cure.

SHATNER: Stonehenge, a healing sanctuary?

But why would people struggling with illness

think that this stone circle could cure them?

PHILLIPS: Some of the stones at Stonehenge are called bluestones.

There's only one place that bluestone

can be got in the British Isles,

and that's the Preseli Hills in South Wales.

We know that they moved those stones all the way

from South Wales to Stonehenge.

But why would they do this?

Why would they need those very specific kind of stones?

In ancient traditions of the Preseli Mountains

where the blue stones of Stonehenge originally came from,

it states that if you poured water over the stones

and then you drank the water, it would have healing effects.

And the idea was people would come from all over Europe

and actually come to Stonehenge to be healed,

not just using the energy of the stones, but also the water

that was poured over the stones and then drunk.

SHATNER: Is it possible that the blue stones that make up Stonehenge

actually have healing properties?

For some, that sounds rather fantastical and hard to believe.

But for others, it's one of the many intriguing theories

that makes Stonehenge so fascinating.

PHILLIPS: We may never know why they brought the bluestones

from 150 miles away.

We may never know why they built Stonehenge,

because they left no writing behind.

But we do know that Stonehenge

attracts over a million visitors every year.

It attracts new-age travelers.

It attracts occultists.

It attracts ordinary, everyday people.

There is something about Stonehenge

that seems to act as a magnet.

SHATNER: If Stonehenge

really did possess mystical healing powers,

then might it suggest that ancient people

were far more sophisticated than we commonly think?

Perhaps further clues can be found by examining

a massive sculpture located

in Egypt, and more importantly...

...what lies beneath it.

Sitting atop a plateau just a few miles west

of the Nile River is the Giza Necropolis.

Perhaps the most famous collection

of ruins in the entire world.

Believed to be constructed during

Ancient Egypt's Fourth Dynasty,

around 2550 BC,

these limestone monuments attract

thousands of tourists every day,

who come to marvel at the immense pyramids,

forbidding tombs,

and a mysterious stone sentinel

known as the Sphinx.

I think you can argue that the Sphinx

is the most recognizable statue anywhere in the world.

Its scale is immense.

It's one single piece of stone.

It is cut from the natural rock of the Giza Plateau.

SHATNER: The Sphinx stands 240 feet long,

66 feet tall,

and 62 feet wide.

For thousands of years, this massive statue

has been an object of both fascination and wonder.

But even after centuries of study,

the Sphinx holds many secrets

that archaeologists are still trying to unravel.

The Sphinx that we know today--

the Sphinx from the Great Pyramids of Giza--

is the most famous of all sphinxes.

But there are sphinxes all over ancient Egypt.

There are smaller sphinxes.

There's an avenue full of sphinxes

between the temples.

NAUNTON: But the Great Sphinx at Giza is something very different.

It's a single sculpture.

It sits in a very particular place.

It doesn't seem to have preformed

the same function at all.

What was it for?

This is what we really want to know.

No one has understood exactly what it means.

Because, for literally thousands of years,

the Sphinx was buried up to its neck in sand.

So, it's only a head sticking out of the sand

for much of its history.

NAUNTON: There is a very famous painting of Emperor Napoleon

standing in front of the Sphinx,

buried still at this point up to its shoulders.

You might think, "What has Napoleon

got to do with Egypt and the Sphinx?" Well, in fact,

Napoleon led an invasion of Egypt in 1798,

which had a big impact back in Europe

in raising awareness and interest in ancient Egypt sites.

SHATNER: It wasn't until the 1920s that a team of archaeologists,

led by engineer Émile Baraize,

succeeded in unearthing the Sphinx from the desert sands.

They were able to expose it and to reveal,

for the first time in centuries,

that this was not just a head, a disembodied head,

but a full Sphinx sculpture.

And this is a watershed moment

for our understanding of the Sphinx.

Archeologists and Egyptologists like myself believe that

the Sphinx was sculpted around 2500 BC

by King Khephren,

as a part of his funerary complex.

But a lot of scholars disagree about the Sphinx,

and there's a lot of mystery surrounding

when was the Sphinx actually sculpted.

One of the most important documents we have

to do with the dating of the Sphinx

is the Inventory Stela.

This is a commemorative stone that actually records

details of how the Pharaoh Khufu

repaired the Sphinx after it was struck by lightning.

The significance of this is that Khufu

came before Khafre, the pharaoh who is

conventionally said to have constructed the Sphinx.

SCHOCH: The Inventory Stela has an inscription

that goes back to about

4,600 years ago.

And that inscription says

that the Sphinx

is a much older structure

that the Egyptians adopted

and repaired and venerated.

SHATNER: Based on the inscriptions on the Inventory Stela,

there are some archaeologists who believe

that the Sphinx is so ancient

that it could predate any records

in human history that are known to exist.

And some researchers are convinced

that physical evidence of the Sphinx's true age

can be found on the structure itself.

SCHOCH: The first time I visited the Sphinx

was in the summer of 1990.

My early studies of the Sphinx looked at the erosional features

on the body of the Sphinx

and comparing that to other erosional features

right on the Giza Plateau.

And what I found was the body of the Sphinx

and the walls of the Sphinx enclosure

are weathered differently than everything else

on the Giza Plateau.

The rest of the plateau

shows classic wind erosion,

but what is on the Sphinx is water weathering.

It's rainfall, precipitation,

and this makes no sense

when the Sphinx is sitting on the edge

of the Sahara Desert that has been a bone-dry desert

for literally thousands of years.

So, what I concluded is that the body of the Sphinx

and, therefore, the original statue

had to go back to pre-Sahara times,

when there was a much more temperate climate,

much more moisture, much more rainfall.

I now think that it goes back

to the end of the last ice age,

circa 10,000 BC.

I am convinced that it is a ruin

from Predynastic Egypt.

SHATNER: Is it possible that the Sphinx was constructed

more than 12,000 years ago?

Centuries before the ancient Egyptian civilization

even existed?

If so, who carved it? And for what purpose?

Some researchers believe the answers to these questions

will be found in a secret room

hidden beneath the Sphinx.

NAUNTON: Something that there's been a lot of speculation about,

regarding the Sphinx is that there is some kind of chamber

hidden underneath it.

A psychic named Edgar Cayce,

in the first half of the 20th century,

asserted that there would be such a chamber,

and that this was the legendary Hall of Records,

which would reveal very great secrets

relating to an ancient civilization

responsible for creating the Sphinx

and all these great wonders.

He also suggested that this would be discovered

by the end of the 20th century.

It was only confirmed relatively recently

that excavations discovered

a passageway in the Sphinx.

ROMANY: There is a tunnel

that was found under the paw of the Sphinx.

A tunnel that people believe connects to another structure.

We have not discovered

what happens at the end of that tunnel.

Where does this tunnel lead to?

Someday in the future, we might find a room

that we've never heard of.

So, the more we dig, the more we find

about the secrets of Ancient Egypt.

What lies at the end of the tunnel under the Sphinx?

Could there be proof that this ancient structure

is more than 10,000 years old?

For now, the answers remain buried beneath the sand.

But there's another ancient ruin

located in northwestern France that is no less fascinating.

It's a site where thousands of massive stones

were placed using an advanced mathematical principle

that was centuries ahead of its time.

SHATNER: This peaceful countryside,

located in the northwest part of France,

is known for its rustic farms and wide fields.

But jutting out from the green hills

is something rather striking.

It's a formation

of more than 3,000 stone monoliths

that stretches across the landscape

for an astonishing two miles.

These monoliths are collectively known as

the Carnac stones.

Carnac is like enormous, stationary giants or needles

plugged into the earth

stretching as far as the eye can see.

It's a unique phenomenon

from any of the ancient sites because none of the others

have these marching processions of stones

in pretty straight lines running on for miles.

There's no other place in Europe or the UK

that we see this kind of arrangement.

Within Carnac is Europe's

largest single megalith.

It was called the Menhir of Er-Grah.

Now it's fallen over, broken, and it's in four pieces.

But it was originally 60 feet tall

and over 300 tons.

At Carnac, there are thousands and thousands of stones.

But the real draw are these alignments,

with neat rows of megalithic stones

going in a single direction.

ERIN KAVANAGH: Carnac has three main alignments,

one of which is particularly interesting.

It consists of 1,050 stones

across ten different rows,

and these are aligned east to west,

and they decrease in size towards the east.

So, there was definitely some sort of plan

going on with the alignments.

But what that plan is remains a mystery.

SHATNER: According to archaeologists,

the Carnac stones were positioned

in approximately 4000 BC,

making them older than the Great Pyramid of Egypt.

But who constructed this extraordinary array

of monoliths and aligned them

with such incredible precision

remains a mystery.

There's a huge amount of folklore about Carnac.

The monoliths are often seen as sinners

who are turned to stone by the Almighty

for breaching a whole range of, uh, religious rules.

Some see them as an army of the dead that rose up

and began marching and then got turned into stone

as death reclaimed them.

KAVANAGH: There's also a theory that involves Merlin

the wise man,

and that there was an invading Roman army,

and to protect the local peoples,

Merlin cast a spell upon the Roman soldiers

and turned them all into stone.

And that's why you have nice, neat alignments.

SHATNER: The fantastic legends surrounding the Carnac stones

may suggest that they had a mystical origin.

But many historians believe the ancient monoliths

are so perfectly aligned not because of magic

but rather mathematics.

The alignments in Carnac are spectacular and elaborate.

The scope of them is astonishing.

But also, the alignments are geometrically perfect

in that there are Pythagorean theorems

built within the stone alignments.

SHATNER: For decades, some archaeologists

have argued that there appears to be

precise triangles

within the monolithic structure.

Historians find this extraordinary because

the Greek philosopher Pythagoras developed this geometric concept

in the sixth century BC,

more than 3,000 years after the Carnac stones were erected.

MICHIO KAKU: When you take a look at the location of the stones,

you could say, "Well, yeah,

there's a Pythagorean triangle there."

And just remember,

these monoliths date back 6,000 years.

So, the ancients were much more advanced

than we give them credit for.

SHATNER: If the builders of the Carnac stones

used the Pythagorean theorem thousands of years

before it was first defined,

then how did they obtain such advanced mathematical knowledge?

It's a profound mystery,

one that Alexander Thom,

a professor of engineering at Oxford University,

tried to answer in the 1950s.

BARNHART: Alexander Thom really

was on the quest to show us just how sophisticated

these megalithic engineers and builders were.

And he determined that by measuring

about 600 different stones,

that there was basically a megalithic yard,

and by yard, he meant yardstick.

It was basically 2.7 feet, is what he thought

was the unit of measure used to create these stones.

KAVANAGH: According to Alexander Thom,

the megalithic yard was precise to the millimeter,

and that this was used to make the mathematical judgements

inherent within these stone configurations.

And he considered it to be a very serious scholarly idea.

Alexander Thom believed that people across

time and distance--

such as between Stonehenge and Carnac--

were using this megalithic yard.

And we can see this in the evidence

that they leave behind

with the alignments and enormous monoliths.

McGOWAN: There's certainly a connection between the standing stones

in Britain and the alignments in Carnac.

However, that is just scratching the surface.

I don't think we even have the first idea

of how extraordinary the intelligence was

that created these alignments in Carnac.

And Carnac needs and deserves so much more study

to understand how exceptional

these ancient monoliths actually are.

SHATNER: Do the incredible Carnac stones hold further secrets

that we have yet to uncover?

Only time will tell.

But there's another ancient wonder,

located on the other side of the world in Southeast Asia,

that might be just as impressive

and even more mysterious.

SHATNER: Perched on a cliff 3,600 feet above sea level

is something that, at first glance,

appears to be an impossible sight.

It's an enormous boulder that is covered in gold leaf

and hangs precariously over the edge of a cliff.

This giant rock is the size of a two-car garage

and looks like it's about to fall off the precipice,

but, incredibly, it never has.

This extraordinary stone is known as the Golden Rock.

NEWMAN: The Golden Rock in Myanmar

is one of the most important sites in the Buddhist world.

It's a 600-ton granite boulder.

And the way it sits on the side of this kind of cliff,

this mountaintop is absolutely amazing.

You can actually almost get underneath it.

And if you sneeze the wrong way at the wrong angle,

it feels like it would just knock it off.

But it's been there for thousands of years.

DAVID MIANO: Everybody wonders how this rock doesn't fall.

It's 50 feet high and 25 feet in diameter.

How it doesn't fall?

It seems to defy the laws of physics.

It's a Buddhist holy site,

and so, on top of it

sits a pagoda 24 feet tall.

And yet we still can't figure out how it's not falling.

DOMINIC STEAVU: This is the holiest of objects for Buddhist people,

and it has indeed become a site of pilgrimage, um,

that is active throughout the year.

Pilgrims make offerings by applying

little squares of gold leaf,

and over time, this-this gold leaf has accrued

all over the rock to the extent that it is now covered in gold.

The earliest reliable documents

attesting to the Golden Rock being a site of pilgrimage

go back about 500 years to the late 15th century,

and these documents are tied

to the Kingdom of Thay Taung

and, um, their official stately documents.

However, there is reason to believe

that the Golden Rock goes much further back

in history as a sacred site tied to the Buddha and that, in fact,

it might go back all the way to the time of the Buddha

in the fifth century BCE, so roughly 2,500 years ago.

SHATNER: Was the Golden Rock erected thousands of years ago?

And if so, how did this giant boulder

come to be positioned in such a precarious way?

Perhaps the answer can be found by examining

why Buddhists consider it to be such a holy site.

COLLINS: At some point in the distant past,

it is said that the Buddha

gave a monk a single piece of hair.

And the monk

accepted this and handed it over

to the ruling king.

And the king said that he would find a suitable shrine

so that it could be placed on top of that hair.

And apparently, they searched everywhere.

And at the bottom of the ocean found this huge, great boulder,

and it was then carried to the top of this mountain

and placed in this incredibly precarious manner.

And underneath it, apparently,

is the actual hair of the Buddha.

SHATNER: The notion that a single hair--

even one from the Buddha himself--

is preventing a 600-ton boulder from succumbing to gravity

does seem a bit far-fetched.

So, why doesn't it fall?

Well, according to some experts, it's likely due

to an incredible feat of ancient engineering.

The word "engineer" means ingenious.

And if you look at the relationship between

the Golden Rock and the edge of the cliff,

what we see is perfect balance, if you like.

The center of the weight of that piece of rock

is going through the point that it's connected

to the stone below.

It must be, otherwise, it would be falling off the edge.

I would say that's nearly impossible,

but the thing to remember about the ancient people

who created these marvels that we see around the world

is that they understood mathematics

and they understood physics.

SHATNER: Is it possible that the Golden Rock

is simply an ingenious feat of ancient engineering?

Perhaps.

But for the faithful,

the mere existence

of such a wondrous sight is more important

than how it was achieved.

What the Golden Rock says

about humanity

is that people

need to feel in contact with the divine.

For the pilgrims who go to this sacred site,

it can be an incredibly powerful and moving experience

to be in contact with something

that is most sacred and most holy in your tradition.

And this is no different from the motivations

and what drove people to visit this site

for the last thousand, 2,000, 3,000 years.

SHATNER: The Golden Rock is proof that, despite our best efforts,

some ancient wonders still simply defy understanding.

Another example can be found in the jungles of Costa Rica,

where archaeologists have uncovered a number

of curious stone spheres,

and no one knows for certain

why they were carved.

SHATNER: Not all ancient ruins are as massive

as the sprawling lost city of Caral

or the majestic Sphinx in Egypt.

Some are much smaller and appear at first glance

to be rather simple.

That is, until you look closely

and realize that, sometimes,

the simplest structures can be among the most astounding.

In the Diquís Delta of Costa Rica,

there are over 300 stone spheres of various sizes

scattered across 25 acres of jungle.

Archaeological evidence dates the earliest

to approximately 200 BC.

But why they were made and who made them

remains a mystery.

NEWMAN: All of the spheres in Costa Rica

are carved and shaped, uh,

created from different types of rock.

Over 300 have been discovered.

These range from the size of a tennis ball

all the way up to nine feet in diameter.

They're very precise. They're very abstract.

They're bizarre in their own right.

The spheres in Costa Rica are, um, fabulous

and fabulously interesting.

They almost sort of demand a story.

There has to be a story behind it.

And so, this, of course has caused people

to wonder a great deal about where these come from.

Are they man-made or natural-made?

NEWMAN: Some people believe that the ancient spheres of Costa Rica

are from Atlantis or from other lost civilizations.

Different people say they are navigational tools.

Some people suggest

they're even mapping the stars on the ground.

As the stars and the planets moved around,

you'd move the spheres around to match it.

One of the traditions that goes way, way back

with the Costa Rica stone spheres

is the idea that, at the center of the spheres,

there's a black stone.

Many of the stones got cracked open

to find that there was nothing in them,

but some of them actually did have

a black stone in the center.

How they would know that,

how they would know, indeed,

that there was a black stone in the center

is another mystery in itself.

SHATNER: Just what are the Costa Rican spheres?

Even with all our knowledge of the past,

all our modern technology,

we still don't know why they were carved

so perfectly in stone.

Despite everything we've learned about ancient ruins,

the ingenuity of our ancestors

continues to mystify us.

While the remarkable feats of engineering

that have already been discovered

offer some clues as to how mankind

once survived and thrived,

there's no doubt that, buried under the desert sands

or hidden in dense jungles, is an enormous amount

of human history that, for now, remains

unexplained.

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