- Tonight, one of the most puzzling
archeological sites on Earth.
- Machu Picchu is a very mysterious place.
Why build a city here?
- People keep digging for answers,
and for some it's even become an obsession.
- 500-year-old secrets hidden in skeletons and stone.
- Some of the skulls that were found didn't even look human.
- It could be the most important archeological find on Earth.
- You look at these single stones
and see how perfectly they're fit.
There's not a good explanation
for how people were able to do that.
- Now, we explore the top theories surrounding one
of the ancient world's most enduring riddles.
- How did they develop
such an accurate understanding of time and space?
- Some people think that there's a much more ancient history
to Machu Picchu we're unaware of.
- Who built this astonishing complex and why?
[mysterious music]
- [Laurence] It's the morning of July 24th, 1911.
Deep in the jungles of Peru,
Yale University Professor Hiram Bingham is
on a quest to find an infamous lost city.
- There's a story from 400 years ago
about the end of the Inca Empire,
when the Spanish came in and took them over,
that they took all of the king's gold
and hid it in a place that is called Vilcabamba.
And that has become a myth called
the lost city of Inca gold.
- By the turn of the century,
as far as historians were concerned,
Vilcabamba was like Atlantis.
It was a fairytale.
Hiram Bingham disagreed.
He wasn't a trained archeologist.
He was a professor at Yale, but he believed very deeply
that Vilcabamba existed and that it could be found.
- There was still persistent talk
by the time Bingham made his first journeys
to Peru, about this lost city,
where there was a huge stash of Inca gold.
- When Bingham arrives to Peru in 1911,
he meets with a Peruvian scholar who suggests
that he's seen in maps, information
that there are a series of very impressive Inca sites
along the Urubamba River.
- [Laurence] Beginning on July 19th, 1911,
Bingham's team bushwhacks its way
through perilous jungle terrain,
determined to find the lost city.
- He has to this deadly river,
and then up this steep, jungle-covered hillside
that's infested with poisonous snakes.
- When he finally reaches the top elevation,
he's expecting something that would be striking immediately.
And it's just essentially a farm.
It doesn't have the immediate gut punch
that he was looking for.
- [Laurence] That is, until he turns a corner
and takes in a shocking sight.
- He can tell that
there's approximately 200 stone structures
that are buried underneath the foliage.
- Bingham is somewhat impressed by the site
that is nevertheless still covered by the forest.
It's unclear to him what is it exactly,
but he senses that this might be the lost city of the Inca.
- It could be the most important archeological find on Earth.
- [Laurence] Bingham and his team go on
to uncover five square miles of what are Inca ruins,
dating back several centuries.
Locals tell Bingham the site is called Machu Picchu.
- The Inca are really well known for their incredible stonework,
which is called ashlar masonry,
and the stones fit together perfectly without any mortar.
It's almost like a jigsaw puzzle.
They did not have the advanced technology
that we have today, so it's really a marvel.
- You cannot fit a dollar bill or a razor blade between them.
The technique of fitting these blocks together
baffles archeologists and engineers today.
- [Laurence] Bingham marvels at the structures
that kept Machu Picchu standing for so long,
and wonders if these ruins could be Vilcabamba.
He also notices that a grand plaza separates
the agricultural terraces on one side
and a grid of closely-packed buildings on the other.
- There's a lot of different kinds of architecture
on the site, which suggests that it was used
for a lot of different purposes.
- Machu Picchu is a very mysterious place.
Why build a city here?
Was it an outpost?
Was it a secret agricultural place?
- Because the Incan people had no written language,
we have to rely on what record keeping was kept
by the Spanish conquistadors.
So what took place in Machu Picchu,
what it was used for, remains a mystery to us.
However, Hiram Bingham does have some ideas.
[tense music]
- [Laurence] The Inca Empire was founded
in the early 15th century
by a king named Pachacuti.
- Pachacuti is known
as the Alexander the Great of the Inca Empire.
He's the one that started to expand the Inca state
from being a very small state centered in Cusco,
just suddenly exploding like a supernova across the Andes.
- [Laurence] What started as a tribe
of around 100,000 people
grew over the next a hundred years into an empire
of more than 10 million,
stretching over 2,500 miles from north to south.
- The Incan Empire excels at government,
architecture, agriculture.
And the Incan Empire was celebrated
for the rumored abundance of gold.
- [Laurence] Inspired by rumors of treasure,
Spanish conquistadors arrive in Peru in 1532.
- The Inca Empire will never be the same.
There's no competing with the horses,
with the guns, and the disease.
Smallpox ended up killing 90% of the native population
in all of the Americas.
From the Spanish records,
we know that the last Inca king retreated to Vilcabamba
with about 100 people,
and they evaded Spanish invasion for nearly 40 years.
- [Laurence] Based on Machu Picchu's
nearly inaccessible locale,
this seems like the perfect spot
to hide treasure and people.
- The longer Hiram Bingham studied this site,
the more apparent it became that a large number
of people lived and died at Machu Picchu.
- During Bingham's first expedition,
he only spent a day up at Machu Picchu.
He didn't know what to make of it,
but he came back for two more expeditions
and started doing excavations at Machu Picchu
for the first time.
What is this?
Could this possibly be Vilcabamba?
- [Laurence] Bingham unearths large burial sites.
What he finds appears to confirm his theory
that he's found the lost Inca city.
- Upon examining these graves,
Hiram's team determines
that over 80% of them must be female.
- Through that, he hypothesized
that this was one of the cloisters of chosen women.
- The Incas had a group of women called
the Virgins of the Sun.
They'd find a girl who was pretty and perfectly formed,
and they would take her to this kind of a convent
when they were about 10 years old.
- Bingham believed that this was Vilcabamba
and that the last emperor retreated there
with these Virgins of the Sun.
And in 1913, "National Geographic" devotes
an entire issue to this incredible find.
- But Bingham's crew does not find
the legendary stores of gold that they were looking for.
- [Laurence] Despite his disappointment
at the lack of treasure,
Bingham is convinced that Machu Picchu is indeed Vilcabamba.
He even writes the 1948 memoir about the lost city
that becomes an international bestseller.
- Until his death in 1956, he continued
to argue Machu Picchu must have been
the last lost city of the Inca.
And it's said that he may have been one
of the inspirations for Indiana Jones.
- [Laurence] But by that time, a growing number of historians
and archeologists believe Bingham's wrong.
- Bingham's expert took a look at the skeletons,
and they looked thin and small
and he concluded that they were women.
But these were indigenous Quechua people
who are slight of build.
- More recent studies have shown that there was, in fact,
a fair balance between men and women.
- Even more importantly,
the Spaniards had sacked Vilcabamba
and they burned the whole city.
But Machu Picchu was pristine.
There was no ash, there was no burned anything there,
so it didn't seem to fit.
- [Laurence] Bingham's theory seems to hit a dead end
in 1964, when American explorer Gene Savoy
reveals the true location of the lost city of Inca gold.
- Gene Savoy excavates a site called Espiritu Pampa,
which was a site that Bingham had actually traveled to,
but Bingham dismissed it.
In fact, he did not go far enough
into the ruins to realize how large it was.
Gene Savoy was able to do enough research
to realize that the Espiritu Pampa was Vilcabamba,
the actual lost city of the Inca.
- [Laurence] Savoy has found the true Vilcabamba,
but alas, no gold is found there either.
- According to the Spanish records,
when they did finally find Vilcabamba,
they melted down every gold
and silver thing they could find.
- [Laurence] If Machu Picchu isn't
the lost city of Inca gold,
then what could it be?
- You can't deny the strategic location of the site.
It's very high up on the mountains,
surrounded by the river on basically three sides.
[tense music]
- [Laurence] For almost all of its 100-year existence,
the Inca Empire is at war
either with neighboring tribes, Spanish invaders, or both.
- The Inca Empire was a patchwork
of other cultures that they absorbed.
Some of them were in an almost constant state of rebellion.
- [Laurence] Machu Picchu's remote location
makes it easily defendable.
- The access to Machu Picchu is very limited.
There's a formal entrance
where there was a very narrow path cut
into the side of a cliff.
At one point, there's a bridge.
Below is thousands of feet,
so if you fall, you die.
- And once the planks are removed off this bridge,
the access to Machu Picchu is completely cut off.
- And attempting to scale the cliffs below
would present an incredible disadvantage against
anybody who wanted to siege the city.
- Machu Picchu has such a unique strategic position,
located on the edge of the mountains in the rainforest,
which means it can watch three boundaries at the same time.
- So if you wanted a first line of defense,
that's where you'd put your citadel.
- [Laurence] Even so, some historians note
that Machu Picchu architecture isn't typical
of Inca military outposts.
What's inside the many grave sites raises further question.
- The Inca were known for burying their dead
with implements that were important to the person
during their life.
But we don't see anybody buried with implements of war
or skeletal injuries that would be related to war.
And so a military fortress probably was not
the main purpose of the site.
- [Laurence] Ever since Hiram Bingham introduced
the modern world to Machu Picchu,
scholars have puzzled over its purpose.
- Because the site is so interesting
and still so well preserved,
people keep digging for answers
and for some it's even become an obsession.
- [Laurence] In 1987, one expert searching
through historical archives
in the former Inca capital of Cusco, Peru
makes an amazing discovery.
- The Inca did not leave a written record,
but in the 1500s, Spanish began to interview some
of the descendants of the Inca
to write down these oral histories
and leave somewhat of a record of the Inca past.
An anthropologist was in Cusco,
poring over some of the records that were in the archives,
and came across a letter from 1568
that said that there was a royal palace.
- It outlines a court case
in which an Inca family was demanding the return
of their lands that included a mountaintop palace
that was named Picchu.
- Not only does it describe generally
where Machu Picchu is located,
but the Peruvian descendants who bring this claim
to the Spanish conquistadors claim themselves
to be descendants of Pachacuti.
- [Laurence] Suddenly, there's a brand new explanation
for this settlement in the sky.
[tense music]
- After he spent the first part
of his time as Inca king expanding the empire,
Pachacuti spent the second half
of his life building these royal retreats
that were on the outskirts of Cusco.
Many of these palaces are very similar architecturally
to what we see at Machu Picchu.
- [Laurence] Based on Spanish records,
many historians agree
that Pachacuti was probably involved
in Machu Picchu's construction.
- The Inca royalty itself was divided
into a series of royal lineages.
Each of them had royal estates.
It's possible Pachacuti's descendants
would spend time in Machu Picchu, probably relaxing.
- Machu Picchu was at a elevation of 8,000 feet.
That's 3,200 feet lower than the elevation of Cusco.
So during the nights, it was much warmer
and it was a much more pleasant atmosphere
in the middle of winter.
- If we look at Machu Picchu as a palatial residence,
the layout makes sense.
There are clearly sectors that are the most private,
the largest and most elaborate rooms.
- There's one dwelling at Machu Picchu believed
to have been the residence of the Emperor Pachacuti.
That residence is the only one that had its own bathroom
with flowing water through it.
- [Laurence] A reexamination of Machu Picchu's dead
reveals new information about who else lived here.
- They're just buried in the ground
and though they have objects,
they seem like everyday wares.
- The lack of treasures indicates
that these bodies were not necessarily royalty,
but they also don't have the same kind of injuries
and arthritis that would indicate
that they were laborers either.
- Those graves that Bingham dug
are really the servants and staff of the city.
- [Laurence] A technique called isotopic analysis tells us
even more about Machu Picchu's residents.
- Archeologists can take a small sample of bone
and vaporize it, essentially,
examining the DNA for traces of the diet
of the person while they lived.
And they found that these individuals ate a lot of corn.
- Corn was, in fact, a symbol of status among the Inca.
And what they find is these people ate mainly corn
because of their privileged status
as retainers and servants of royalty.
- [Laurence] There are more clues to be found
by studying the skulls.
- Some of the skulls that were found were very bizarre
and they didn't even look human.
- Some of the skulls have cranial deformation
and seem to be squished to a higher point at the top.
- It's really well known in the history of the Andes
that the people would bind their heads into different shapes
that had to do with an ethnic identity.
This was often done when an individual was born
and their head was very malleable.
- [Laurence] Modified skulls are not the only clues
that Machu Picchu was a royal hub.
- From the ceramics that were left in the burials,
they could determine this was a real heterogeneous
accumulation of people throughout the empire
who were actually at Machu Picchu working
as metallurgists, attendants, and staff.
- [Laurence] Leading researchers suspect Machu Picchu
was a place for Pachacuti
to entertain a vast array of guests.
- We can think of it as a 16th-century Camp David.
In addition to the varied visitors
that may have come to the site,
there were people that had to work there
to grow the crops, tend to the fields, to cook the food,
to make the crafts and the goods that were used.
So these discoveries have led to the idea
that this could have been a royal retreat
where people were coming from a variety
of different locations from around the empire.
- [Laurence] Many scholars speculate
that Machu Picchu was built in the mid-15th century
as a winter getaway for Inca Emperor Pachacuti
and his entourage.
But could the site have a more serious purpose?
- If political entertainment
and relaxation are the primary activities
that are being done at Machu Picchu,
then why all of these spaces that seem to be devoted
to religious ceremonies?
- Parts of the architecture
and the landscape where the site was built really suggest
that there is a sacred purpose behind Machu Picchu,
which is really significant when we think
about Inca worldview
and how they worshiped both their ancestors and the gods.
[tense music]
- In terms of the way in which the Inca worshiped,
we can't be entirely sure,
but we do know that they worshiped a number of gods.
[thunder rumbles]
- Illapa's the god of thunder, god of the weather,
god of rain.
Beneath that, it was a vast assortment of gods
and a host of spirits.
- Viracocha was the creator god
and one of the most prominent and important,
but Inti, the sun, was also very important to the Inca.
- During his first visit,
Bingham came across this curved wall
that caught his attention.
He famously called it the Torreon,
right, the turret or tower.
It really resembles the Temple of the Sun found in Cusco,
which has led scholars to believe
that this was another Temple of the Sun.
- Hiram Bingham was fascinated by this,
not only because of the rare curved architecture on top,
but it was built on top of a cave
that had itself very intricately carved stone.
- It's also very close
to what we believe to be the king's quarters.
There were places where it was the king's obligation
to honor and remember the deeds of Viracocha.
So he, as the son of the sun,
was probably stationed quite close to the Temple of the Sun.
- [Laurence] But the Inca didn't just worship gods
in the sky, they also worshiped water.
- The Inca are world renowned
as some of the most amazing hydraulic engineers
the ancient world ever knew,
and Machu Picchu is an incredible showcase
of their abilities.
- Not only did the Incan people believe
that it was access to water that gave you power,
but also that their ability to control that flow of water
was something that was given to them by the gods.
- For the Inca, everything is alive.
Pachamama, or Mother Earth, was very important
to this Inca spirituality.
And Pachamama had to be nourished through
different kinds of water rituals.
- [Laurence] Archeological studies suggest
that a site on the perimeter
of Machu Picchu called Chachabamba
was built specifically for the worship of water.
- Chachabamba was discovered in 1940,
a series of 14 sacred baths
that are believed to be a very key part
of their ceremonial services.
- Recently, some researchers went in
and did drone LIDAR work,
using lasers to map the ground,
and then you can remove that canopy of trees
and see what's below it.
And they were able to see
that there were a lot more conduits
that were diverting water from waterfalls
that were further away.
- [Laurence] But why here,
just two miles down the road from Machu Picchu?
- Some archeologists believe that Chachabamba
was a place where a traveler would stop to purify their body
and their soul on their way to Machu Picchu.
In 2009, a theory emerged that Machu Picchu
was, in fact, a destination for a spiritual pilgrimage,
a way to celebrate their origin story.
- The creator deity Viracocha called up the sun
and the moon first from the Island of the Sun
in Lake Titicaca.
He then used clay from the sides of the lake
and created the first people,
and they take the journey to establish Cusco
as the capital of the Inca Empire.
- The idea is that the baths
of Chachabamba are like Lake Titicaca.
One immersed themselves in this water.
Then the two-mile walk up to Machu Picchu represents
this walk across the land.
- If Machu Picchu was indeed a pilgrimage site,
we can picture people approaching the city
and conducting cleansing rituals
in places like Chachabamba and other sites.
- [Laurence] Pilgrimage or not, scholars believe
that many of the structures within Machu Picchu
served a religious function.
Among them, the Temple of the Three Windows.
- When Viracocha sends the people to Cusco,
he sends them in a cave entrance near Lake Titicaca.
And there are three cave exits,
so three windows symbolizing those three exits.
- [Laurence] Another feature of Machu Picchu
seemingly built for religious use
is the Temple of the Condor.
(condor shrieks]
- The condor was a sacred creature among the Inca.
They thought that the mountain gods could transform
themselves into condors and vice versa.
So not surprisingly, at Machu Picchu,
there's this big temple,
and they actually carved out of the bedrock
two wing-like structures and the head of a condor.
That's a place where they could offer sacrifices.
- [Laurence] Some of those sacrifices may have been animal.
- Some archeologists believe
that the Temple of the Condor was used
for sacrificing guinea pigs and llamas
as a symbol of power and fertility.
- [Laurence] And some offerings may have been human.
- There's a specific Inca ceremony called the Capacocha,
and it's very well known that young children were chosen
to be sacrificial victims when there were times of trouble.
- That seems very barbaric from Western society,
but if you are in an environment where you believe
that the gods need your sacrifices,
children are the absolute most precious thing
we could sacrifice.
- Machu Picchu may have been the place
for the ultimate sacrifice.
- Because the Incas were dependent upon all
of these spirits and gods around them,
it was very important
to maintain a good relationship with them.
And the way they felt they could best do that was
to offer offerings to them on a regular basis.
- We see this in various parts of the empire.
Children that were sacrificed have been found,
but there's no evidence of the Capacocha ceremony ever
to have took place at Machu Picchu.
We have not found any remains that relate to that.
- But you really can't deny that there would've been
some religious and spiritual use for these buildings
when the population itself was so tied
to their spiritual recognition
of these places and these entities.
to their spiritual recogn thany
since Hiram Bingham introduced Machu Picchu to the world,
and even after decades of scrutiny,
the site is reluctant to give up its secrets.
But the Inca did leave clues behind,
including ones that suggest
the site filled a very practical purpose.
- The Inca really had a phenomenal understanding
of the movement of the celestial bodies.
They were very spiritual
and they very much revered the sun and the moon.
- Incas obviously didn't have clocks and watches,
so they used passage of the sun
to determine their clock, so to speak.
The rocks themselves were like little sundials
so they could tell by the shadows on the rocks
what time of year it was, what time of day it was.
- Tracking the movement of the sun is very difficult
in itself, but they accomplish this with a lot of precision.
So the Temple of the Sun especially noteworthy
because, although it might seem
that it's just a beam of light projecting into the wall,
there's much more to it.
- The architecture reflects and encompasses
how they could have had such a precise understanding
of the movements of the cosmos.
[tense music]
- [Laurence] The Temple of the Sun
isn't the only building in Machu Picchu
that marks the sun's movement.
- There's at least two observatories in Machu Picchu.
One marking the summer solstice,
the other one, the winter solstice.
Beneath the Sun Temple, there's this cavity there
and is exquisitely cut stones, like stairways.
And the name of that carved area underneath the Sun Temple
is called Intimachay, which means cave of the sun.
- The sun enters the cave in June
for a certain window of time.
And in 2012, there was a team of researchers
that went and mapped the inside of this cave using LIDAR
and 3D technologies to really understand the details
inside the cave.
- [Laurence] They discover that this structure
is even more complex than it appears.
- The cave may not have only
had some of these solar alignments,
there's probably some lunar alignments as well
that show that there's much more in-depth understanding
of the movement of the heavenly bodies
than we may even understand
was actually happening at the site.
- [Laurence] While the Intimachay acts
like a solar calendar underground,
another carving tracks the sun from above.
- One of the very prominent features of Machu Picchu is
you go up on this precipice there,
and there's a rock carved right out of bedrock
and it's called the Intihuatana, the Hitching Post of the Sun.
It marks the four points,
north, east, south, and west,
and also it's thought to mimic the nearby sacred mountain
of Huayna Picchu,
which is the famous backdrop of Machu Picchu
because it models the shading of that mountain there.
- So the Intihuatana is this extraordinary measuring device.
And during the equinoxes when the sun is right above it,
it projects no shadow at all.
- It was a place for the Inca priests
to watch the equinox and the solstice,
and they would then ceremoniously tie the sun
to the hitching post
so that it didn't go farther north or south.
- [Laurence] Keeping time by observing the skies
was critical to the Inca.
- The way they're tracking the winter solstice
and the summer solstice
through these buildings becomes extremely important
for the planting and harvesting season.
- The Inca spirituality really was so much about nature,
so being in this location that's high up in the clouds,
you are really immersed in this environment of the gods.
You're close to that celestial movement,
which is so important to the understanding
of when to perform certain ceremonies,
when to harvest plants.
- Without being able to so accurately predict the seasons,
it would've been virtually impossible
for their terraced gardens to have been able
to support the people that were living there.
- So a variety of different kinds of architecture
at the site may have been used for astronomical observations.
- People might think of the Incas
as being a primitive culture,
but they created the largest empire in the New World.
However, on the other hand,
we'll probably never know the extent of Inca cosmology.
- It leaves us absolutely mystified
as to how they could have made these calculations.
How did they develop such an accurate understanding
of time and space?
- [Laurence] Whatever the driving force was
behind Machu Picchu's construction,
it's a testament to the ancient Inca's sophistication
as builders, engineers, and even astronomers.
But not everyone thinks the Inca created this place alone.
- In the 1960s, theories emerged regarding a lot
of structures around the Earth,
Stonehenge, Easter Island, the pyramids,
that suggested that it was impossible for human beings
to have created these architectural feats.
- When you look at a wall on Easter Island called Vinapu,
this building technique is identical
to what you see in Peru.
Perfectly-fitted granite blocks,
would seem they're using power tools
to cut very hard rocks, granite and basalt.
- It was believed that
for human beings to construct anything like this,
we would've had to have been aided
by a far more advanced technology
than was available on Earth at the time.
And according to proponents of the ancient astronaut theory,
we got help from other worlds.
[tense music]
- [Laurence] It may sound like the plot of a sci-fi movie,
but there are some things about Machu Picchu's construction
that defy logic.
- A few stones in the center of Machu Picchu
are over 50 tons.
And you look at these single stones
and see how perfectly they're fit,
there's not a good explanation, to this day,
how people with rudimentary technologies
were able to do that.
It seems impossible.
- The feet of engineering does seem otherworldly at times,
because even though the ashlar technique
was used throughout the Incan Empire,
which was a way that the stones were carved
and they fit together in a sort of puzzle piece,
how do you do it at the top of a mountain?
A closer examination
of the foundations underneath Machu Picchu show
such a significantly different architectural style
that it's possible that the foundations were built
by an entirely different civilization.
- Whether it's extraterrestrials
or some other sophisticated civilization,
who can do these things
and perfectly fit giant blocks of stone together?
- The ancient astronaut theory is considered by many
to be pseudoscience.
However, there is new evidence
that the history of Machu Picchu may be much, much older
than anyone has anticipated.
- There's a long history of civilization in the Andes,
going back to the first cities being built, 3000 BCE,
throughout what eventually became the Inca Empire.
- Some of these carved rocks are as big as box cars,
and archeologists believe that they predate the Incans
by hundreds of years.
- [Laurence] Just a short walk from the center
of Machu Picchu in an area named after Pachamama,
the Earth Mother, stands a large granite outcrop
that's been hiding a secret for over 1,000 years.
- In 2016, one of the Machu Picchu archeologists
discovered a faint symbol that raised some new questions.
- What's found on that panel is a man, a llama,
and some black-and-white geometric shapes.
Some people think that it's an indicator
that there's a much more ancient history
to Machu Picchu we're unaware of.
- Whatever it means,
it has no specific ties to the Incan population
in the 15th or 16th centuries.
- [Laurence] Further exploration of Pachamama
reveals even more puzzling cave paintings,
estimated to have been made as early as 800 AD.
- Perhaps the greatest indication
that there was some association
with ancient aliens comes from the Incan religion itself.
- [Laurence] And there's one Inca legend in particular
that can certainly be interpreted as supernatural.
- There's a legend that the Emperor Pachacuti,
on the eve of a great battle,
went to a lake and is reflecting on what to do next.
And that in this moment, a disc fell from the sky
from which emerged a face.
And the supernatural creature tells Pachachuti
that he's going to win the upcoming battle and many more.
The story is then that these huge monolithic stones
come to life and assist Pachacuti in his battle.
And these levitating rocks
are what helped build Machu Picchu in the first place.
There is no evidence to support any of these stories,
but there are many stories that indicate that the skies
above Machu Picchu today still remain a hotspot
for paranormal activity.
- UFO activity in Peru is quite considerable.
And, in fact, when you're in Peru,
the subject of UFOs is a very common one.
Most people do not doubt the existence
of extraterrestrial sky gods
who had the technology to fly through the sky,
to levitate stones and magically move them.
Is it possible that these same sky gods are the ones
who built Machu Picchu?
It's a common belief there that that is what was happening.
[tense music]
- [Laurence] Nearly 600 years after Machu Picchu was founded,
research teams aren't certain
how Machu Picchu was made, or why.
- It's estimated that potentially up to 60%
of the construction of Machu Picchu is underground,
and these deep foundations were necessary
to help with seismic movements and terrace drainage,
to make sure things would filter properly.
- To keep a place like Machu Picchu securely
on the mountaintop,
it takes under-the-earth infrastructure.
It's entirely possible
that there are subterranean chambers we've yet to contact.
In 2010, an engineer named David Crespy
came to Machu Picchu, looking specifically at those caves
under the Temple of the Three Windows,
and said that structurally, the wall that was in the back
looked like it might be hiding
an entrance into deeper chambers.
- He immediately alerts the other archeological teams
to his discovery, but gets no response.
After enough time goes by,
he reaches out to a French archeologist named Thierry Jamin
to see if he can help see what might be underground.
- [Laurence] Jamin gets approval to search the area
with ground-penetrating radar.
In April 2012, along with a team of archeologists,
he makes a stunning discovery.
- They did some geophysical investigations at the site.
And what he thinks he found
is some kind of a chamber below this door
that may have had a staircase leading into it.
- The radar also indicates a huge amount
of metal down there,
which could indicate silver and gold,
exactly the kind of riches that one would expect
to be buried with royalty.
[tense music]
- [Laurence] Like the ancient Egyptians,
the Incas mummified their great leaders,
not to memorialize their power, but to preserve it.
- They were not fancy burials, and they believed
that their ancestors did not die when they died.
They would go into the afterworld, but their spirit
would remain and would look over their descendants.
- In the chronicles that the Spanish left behind,
they describe instances of them eating
and drinking with these remains,
even building vast palaces as if they were still alive.
So the Spanish Conquistadors were horrified
with the amount of power
that these mummies had over the living.
Maybe this whole place was dedicated to the afterlife.
Hiram Bingham's crew is believed
to have excavated all of the graves on Machu Picchu,
but they perhaps missed the most important one.
- [Laurence] The Peruvian government
denies Jamin's request to excavate further,
but he has a hunch about what or who
may be lying within the chamber.
- Thierry Jamin believes that Pachacuti,
who is one of the legendary builders of Machu Picchu,
would be buried there too.
And his gold mummy was somehow interred inside this wall.
- It's possible that Pachacuti's mummified remains
were once located in the cave
underneath the Temple of the Sun
that Bingham had originally believed was a burial chamber.
- [Laurence] Pachacuti dies in 1471.
According to his wishes,
the whole of the Inca Empire mourns for a year
and then spends a month celebrating his life.
- Although his remains were originally installed
in the capital city of Cusco,
according to the Spanish chronicles,
a person of his stature
would have made regular outings, even as a mummy.
- [Laurence] But after the Spanish conquest
starting in 1532,
just when his people need him most,
Pachacuti's mummy mysteriously disappears.
- In 1559, a Spanish magistrate claims
to have collected, by order of the viceroy,
the deceased bodies of Inca kings and queens,
and then shipped them to Lima.
The bodies were deposited in a hospital
in the city of Lima,
and they were eventually buried there
where we believe they can still be found.
- [Laurence] None of those human remains
have been positively identified as Pachacuti.
- Unofficially, the question remains
were Pachacuti's mummified remains
instead brought to Machu Picchu for reburial?
Is Machu Picchu a location for the life and afterlife
of the Inca's greatest leader?
- [Laurence] Thierry Jamin and his crew are keen to know
if what they've seen on that radar
could really be Pachacuti's tomb.
For now, the truth is staying buried.
- Today, we can't help
but look at Machu Picchu through our Western eyes.
But, of course, it was made by people
who had a very different cosmovision than we do.
Part of the mystery of Machu Picchu is we just don't know
how to look at it the right way.
- Whether Machu Picchu was built for war or peace,
as a place of worship or a place to unwind,
an astronomical wonder or a tomb for the dead,
the search for more answers
about this astonishing site continues.
As top archeologists employ new technologies,
perhaps they will one day decipher the true purpose
of Machu Picchu.
I'm Laurence Fishburne.
Thank you for watching "History's Greatest Mysteries."
[mysterious music]