WILLIAM SHATNER: A vast subterranean chamber
hidden for centuries.
A legendary lost treasure buried in an ancient mine.
And a town in the Australian Outback
that is located entirely underground.
For as long as humans have walked the Earth's surface,
we've also wondered about
what lies beneath our feet deep underground.
Are there profound secrets about our planet
buried beneath layers of rock, or hidden in vast caves?
What can the subterranean world
tell us about humanity's past,
and perhaps even its future?
Well, that is what we'll try and find out.
♪
SHATNER: Human beings have a strong desire to learn
everything we can about the planet that we live on.
After all, we've launched satellites into outer space
that have photographed every inch of the Earth's surface,
and we've used deep-sea submarines
to journey to the bottom of the ocean.
However, there is one final frontier in our world
that remains almost totally shrouded in mystery.
For we have yet to fully explore the vast underground depths
of our planet Earth.
It's really uncommon for someone to know how deep the Earth is.
Very smart people often guess, "hundreds of miles?"
When in fact, it's 4,000 miles to the center of the planet.
L.A. to New York is just a fraction of that,
with the 2,700 miles.
The mass of the Earth is great.
And when you think about the amount of rock
that's piled on rock, on rock,
that pressure is incredible and prevents us from going deeper.
So, what's beneath our feet?
We don't know.
Mankind's relationship with the underground
stems from our innate curiosity,
and the ground beneath our feet is open season for that.
SHATNER: Today, scientists and explorers are compelled
to investigate the subterranean world,
in hopes of shedding new light in the darkness of its depths.
But these efforts are just the latest chapter
in humanity's long quest to learn more
about all that we cannot see beneath us.
In fact, our fascination with the secrets of the underground
stretches back thousands of years.
Going back 3,500 years, we find drawings and paintings
underground where it's completely dark.
So, we can see how our early ancestors
connected mythology to the underground,
in terms of their relationship to the Earth.
These explorations and forays
meant something on a spiritual level.
They were pushing as far as they could go
with the technology that they had.
BRADLEY GARRETT: The underground has always been important
in human history, and it's tantalizing
but it's also kind of frightening.
For instance, we can look to Hades in Greek mythology,
this underworld which is a metaphor
for not being blessed by the light of the heavens.
Also, we can look to Dante
going into the seven circles of Hell in an Inferno.
All of these point to an underground space
that you'll go into and never come out from.
(man screaming)
SHATNER: While often described as a place of danger,
darkness and doom in the legends and folklore
of cultures around the world,
it was during the 18th and 19th century
that the perception of an underground world
became less mythological and more scientific.
This evolution in thinking is perhaps best illustrated
in author Jules Verne's seminal novel
Journey to the Center of the Earth,
which was published in 1864.
LYNNE McNEILL: Jules Verne's Journey to the Center of the Earth
is the story of a professor, his nephew and their guide
going into the center of the Earth
through a volcanic crater in Iceland...
...making their way through these subterranean passages
and finding prehistoric plant life
and creatures and maybe even a suggestion
of some sort of humanlike creature
that they glimpse but don't interact with.
Jules Verne was a well-read author,
he was up on the science of the day,
and he made a really scientific effort
at describing an entire subterranean world.
It's a fictional book,
but it really resonated with people's imaginations.
SHATNER: Journey to the Center of the Earth
had a profound effect not just on science fiction readers
but also on actual scientists,
who were inspired to explore deeper than ever before.
By the 20th century, modern drilling technology
gave scientists a new tool for satisfying
our ongoing curiosity about what lies underground.
The most famous effort to drill into the planet started in 1970,
when the Soviet Union embarked on an ambitious attempt
to reach as deep as possible into the Earth.
The project, which was conducted
on the Kola Peninsula in Russia, lasted for more than 20 years,
and resulted in what is referred to
as the Kola Superdeep Borehole.
The hole, which is nine inches wide,
reaches an astounding 7.6 miles into the Earth.
The Kola Superdeep Borehole
is just a really thin, narrow hole
straight down into the Earth.
One of the reasons why they made the hole that shape
is that the wider the space it is that you're drilling,
the more resistance that you run into.
One of the biggest obstacles
to digging that hole was the temperature increases
about 60 degrees Fahrenheit
for every kilometer that you go down.
These teams found, when they were drilling down,
that the rock started to behave like plastic.
And that the solid rock was actually gumming up
the works of-of their drills.
ROBERT SCHOCH: There's so much pressure there,
there's so much heat there, eventually,
they could drill no deeper and they had to abandon it.
And since then,
there has been no project that has gotten deeper.
It's actually the deepest hole that has ever been drilled
to this day by humans.
SHATNER: While the Kola Superdeep Borehole
is an inspiring feat of engineering,
at 7.6 miles in depth,
it only reaches less than one percent
down to the center of the Earth.
And in fact, many experts believe that instead
of using drills to dig into the underground,
we should instead listen
to subtle vibrations in the earth
that are called seismic waves.
By studying seismic waves,
scientists detected two giant structures
deep inside of the Earth's mantle.
These formations are so oddly shaped
that they are commonly referred to as "Earth blobs,"
and according to experts, Earth blobs pose a dire threat
to the survival of humanity.
GARNERO: These blobs are massive.
Hundreds of miles tall, the size of continents,
very irregular in shape, and they're very hot.
The temperature of the surface of the Sun
is the temperature of these things.
There's the possibility that over time,
these blobs might rise
and come to the surface and would result
in crazy intense volcanic eruptions.
MICHIO KAKU: The gigantic energy
from a volcano comes from underground,
underground from the core of the Earth itself,
creating a catastrophe beyond human comprehension.
And so, when it comes to what's underneath our feet,
we have to watch out.
It's staggering to think
that we've only managed to drill
less than one percent into the Earth's crust.
But even so, archaeologists continue to make
shocking underground discoveries all the time,
such as a baffling man-made cave system in China
that was carved thousands of years ago
by a mysterious unknown civilization.
SHATNER: In a small village,
a group of farmers begin draining several ponds
to create space for new planting fields.
But as the waters recede,
they make a remarkable discovery.
CLEMENTS: The villagers saw
the water was slowly going down
and there were steps going down.
So, they got very excited that this was
some kind of, you know, archaeological discovery.
And when they went inside,
they found that they were in a group
of underground man-made caverns.
SHATNER: Once the water was completely drained,
the villagers discovered a series of astonishing chambers
that had been carved underground centuries earlier.
Further excavations revealed the existence
of 24 massive caverns.
Each cavern covers an area of approximately
11,000 square feet,
or roughly the size of two mansions.
Archaeologists have also noted that the walls, pillars
and ceilings of the caverns were all precisely carved
to have an unusually smooth and symmetrical appearance.
All told, the massive underground complex
measures 320,000 square feet,
which is the size of more than five football fields.
These incredible man-made structures
are collectively referred to as the Longyou Caves.
The discovery of the Longyou Caves
is very fascinating
because there was absolutely nothing to suggest
that there were these carved, beautiful caves
actually beneath the water.
And so, when the actual caves were discovered,
everybody was absolutely amazed
because there was no indication that they existed.
They have these pillars inside them
which are anything up to 100 feet in height.
And there are long corridors.
There's some beautiful relief carvings on the walls
of animals and dragons and things like this
that are of immense sophistication
in their design and the manner that they were carved.
NEWMAN: When you look at the carvings, the chisel marks are so uniform,
there's very detailed shaping of some of the stones.
To the untrained eye, it looks like something created
in the last 20 or 30 years.
Some people suggest the caves
are one of the Wonders of the Ancient World,
but they weren't discovered until 1992.
So this raises so many questions.
SHATNER: Based on the carvings on the walls
and artifacts recovered in the chambers,
archaeologists estimate that the extraordinary Longyou Caves
are roughly 2,000 years old.
While there are similar ancient underground structures
throughout China,
the size and sophistication of the Longyou Caves is unique.
But just who exactly carved these enormous caverns
and why remains a mystery,
because there is no mention of this site
in the historical record.
How is it possible that the existence of 24 caves
can go unrecorded?
This is very strange because the Chinese
have always been very meticulous
in the way that they've recorded provincial data.
And yet, there was absolutely nothing,
no mention whatsoever of these caves.
CLEMENTS: The caves themselves are so massive,
such a huge undertaking.
It's not something that a bunch of local villagers
might have done for a hobby.
We can estimate that it would have taken
a thousand people, working 24 hours a day,
six years to carve out these caverns.
There ought to be some kind of geographical feature,
some kind of odd-looking hill or an infield valley
or something where all that sandstone has gone,
but we don't know where that is.
SHATNER: In recent years,
some historians have suggested that the Longyou Caves
disappeared from history because they were intended
to be secret caverns
that were never meant to be found.
We do not know who built the caves.
But we can guess, considering the fact
that they're 2,000 years old,
that they were built in a period called the Warring States.
And at the time, China was a patchwork
of different kingdoms all fighting each other.
And the fact that they are not mentioned in ancient documents
could well be a factor of their use
for some kind of strategic purpose.
So, "We're not gonna tell the enemy
"where our secret bunkers are.
We're not gonna tell them where our secret supplies are."
SHATNER: Could the Longyou Caves have been a subterranean place
to hide critical supplies
or even people from encroaching enemy forces?
Or could their purpose be tied to the deep waters
that shrouded their location?
What's interesting about the Longyou Caves
is it seems that when they flooded,
the water helped maintain the structural integrity.
Somehow, it took the load off some of the beams,
for example, holding up the roofs.
Now that the caves have been drained,
the Chinese have been obliged to add
extra buttressing to hold them up.
And so, I think they were
a storage facility, um, and I think,
certainly, many of them were intended for water.
The area is drought-prone,
so in the event of some kind of military crisis,
it would have been very handy to have a secret base
with enough water for them to live on for years.
SHATNER: Were the Longyou Caves hidden beneath a pond for centuries
because they were built to be a secret water reservoir?
Or could they have had another purpose,
that has yet to be unearthed?
For now, the answer remains lost to history.
But in modern times, the caves have become
an important source of pride for the people of Longyou,
who regularly hold festivals in this ancient underground space
to commemorate their heritage.
The story of the Longyou Caves is actually very fascinating
because it would seem that by looking
beneath the earth itself,
we're obviously going to discover many, many caverns,
underground chambers or even cities
done by human hands that have been completely lost,
and that's a very exciting prospect.
Archaeologists are conducting ongoing excavations
in an attempt to unravel the mystery
of who built the incredible Longyou cave system.
But some experts believe the best way to solve
an underground mystery is not by digging,
but rather by researching historical texts.
For instance, there's a copper mine
in southern Israel that, according to the Bible,
may have been the hiding place of King Solomon's treasure.
SHATNER: In the deserts of southern Israel
lies a mountainous region that is called the Timna Valley.
Today, this area is known
for its uniquely shaped sandstone cliffs.
But more than 3,000 years ago, the Timna Valley was the site
of a vast network of copper mines.
MULLINS: In the Timna Valley, mining activity took place
for a long, long time,
and most of the mining operations
took place underground.
The deepest is about 115 feet.
They would hew in the ground circular shafts,
and going down that shaft,
they would cut steps into the side of the shaft.
And they would tunnel along horizontally,
where they would extract the copper
and take it back up to the surface.
SHATNER: In recent years, the Timna mines have attracted attention
because there are those who believe
that buried underground in one of these deep tunnels
is the legendary lost treasure of the biblical King Solomon.
In the Old Testament of the Bible,
King Solomon is described as a noble
and wise ruler of Israel.
Historians believe that Solomon was a real person
who lived in the 10th century BC.
King Solomon is an intriguing figure
because the Bible makes so many claims about him
controlling vast amounts of territory.
According to the Bible,
Solomon expanded ancient Israel considerably,
from the Euphrates river in the north
all the way to the River of Egypt,
and so, a much more expansive territory.
The Bible also describes
Solomon controlling vast amounts of wealth.
Solomon decides to build a temple, uh, in Jerusalem.
The temple becomes the home of God,
and he spares no expense.
And he was so committed
to having the best temple in the region
that he actually imports the finest materials
to build this temple.
SHATNER: According to the Bible, Solomon's temple was built
from the best limestone and cedarwood.
Inside, the walls were overlaid with pure gold,
and Solomon adorned the temple with objects made out of copper,
which was also a precious metal at the time.
King Solomon ruled Israel for 40 years
before dying in 931 BC.
Upon his death, Solomon reportedly left behind
an enormous amount of gold and other riches
in his magnificent temple.
But then, in 586 BC,
the Babylonians invaded Jerusalem
and sacked Solomon's temple.
When the Temple of Solomon was destroyed in 586 BCE,
all the temple treasures were lost to history.
An ancient legend says that Solomon's treasures
were taken out of Jerusalem and buried.
There are those who believe that the treasures
are, to this day, still hidden.
SHATNER: For centuries, the legend of King Solomon's lost treasure
has been a source of fascination and mystery.
In 1885, the story was exposed to a wider audience
when author H. R. Haggard wrote his famous novel
King Solomon's Mines,
which speculated that Solomon's treasures
were hidden deep in an underground mine shaft.
But if there is some truth to this legend,
then where is King Solomon's treasure buried?
For some, the most likely location is the Timna mines.
MULLINS: The Timna Valley is located
not more than 150 miles from Jerusalem.
So we're talking about close proximity.
At Timna, there are 10,000 mine shafts, maybe more,
and so, it's easy for people to kind of say,
"There must be a connection."
SHATNER: In the last several decades,
numerous researchers have tried to prove that the Timna mines
are, in fact, the hiding place
of King Solomon's lost treasures.
Some of the first evidence in support of this theory
was found by an archaeologist named Nelson Glueck,
who conducted a series of excavations at Timna
in the 1930s.
COLLINS: Nelson Glueck
made a huge study of the-the copper mines,
the smelting works,
and also, the camps of those that were there.
And what he found under the ground was pottery
dating from the 9th to 10th century BC.
And this was the exact time frame
of the reign of King Solomon.
And so, for Nelson Glueck,
he felt that he had discovered evidence of Solomon's mines.
SHATNER: Nelson Glueck's discoveries
made sensational headlines around the world.
However, despite years of searching,
Glueck was unable to locate the fabled treasure,
and some experts began to think that Glueck was wrong
to associate the Timna mines with King Solomon.
But then, in 2019,
a team of archaeologists led by Professor Erez Ben-Yosef
of Tel Aviv University, made a remarkable discovery.
While excavating an ancient mining worksite at Timna
that is referred to as Slaves' Hill,
they found more evidence that links this location
to King Solomon.
When you take the totality of this,
the Bible and what it says about King Solomon,
the presence of these copper mines in the deserts of Israel,
and put all these elements together,
for people of faith,
it gives them a greater assurance
of the truthfulness of the Bible,
that it involves real people
in real places in a real time.
Is the treasure of King Solomon
hidden somewhere in the Timna copper mines?
Experts continue to search for clues deep underground
in hopes of answering that long-standing question.
Not unlike another subterranean mystery
that has also persisted for centuries.
One that involves the strange theory
that there are vast open spaces
located in the center of the Earth.
SHATNER: Seismologist Dr. Paul Richards
and his team at Columbia University
make a remarkable announcement.
They discovered that while a full rotation
of the Earth's surface takes 24 hours,
the iron core at the center of our planet
actually spins faster.
AGNEW: They were measuring
the rotation of the core of the Earth
in relation to the surface of the Earth,
and what they found was that it's not constant.
And it leads people to believe
that there is a disconnection between the two.
Maybe it's not molten rock.
It could be open air.
So, when you put all of that data together,
it leaves open the idea,
the hypothesis, that Earth is hollow.
Could there really be vast hollow space
beneath the Earth's surface?
It sounds crazy.
And yet, for thousands of years,
the belief has persisted that beneath our feet
there are not just caves and tunnels
but an entire underground world.
The idea of the Hollow Earth is that we live on a shell
and that inside the Earth is a hollow cavity
with its own atmosphere, its own animals,
and possibly, its own inhabitants.
AGNEW: The concept of a Hollow Earth
goes well back before written word.
We have pictograms,
cave drawings, things that describe
either deities coming out of the Earth
or man trying to communicate with deities in the Earth,
and that's where the idea of a Hollow Earth came from.
SHATNER: Of all the ancient tales about Hollow Earth,
perhaps the most intriguing
is one that involves the Garden of Eden.
TZADOK: There is an ancient legend
that is recorded from a very, very old text
called the Sefer HaTemunah, the "Book of the Image."
The legend tells us
that a cave called Machpelah
is the doorway to the Garden of Eden...
...which exists in inner Earth.
But here's the interesting question:
a garden in a cave?
It doesn't work like that.
Gardens have plant life that grows, requires sun.
But in inner Earth, there's an inner sun.
SHATNER: Could Adam and Eve have lived
in a lush paradise deep underground?
The incredible notion that people
could inhabit subterranean spaces
has been embraced not just in ancient times
but also, in the modern era.
In fact, by the turn of the 20th century,
the fascination with Hollow Earth was so strong
that a new generation of scientists and explorers
set out to find proof of the existence
of a so-called "Inner Earth."
Perhaps the most fascinating of those expeditions
was led by an American Naval officer
named Admiral Richard E. Byrd in 1926.
Admiral Richard Byrd
was a famous American aviator and explorer.
And he claimed that on one of the journeys
that he made to the North Pole--
in an aircraft-- he came across
an environment down below that was plush and green
with animals, almost like a sort of Garden of Eden, if you like.
In other words, what was seen, perhaps, by Admiral Byrd
at the North Pole was actually an entrance
into a parallel world,
a parallel existence
that exists and coexists with the Earth itself.
SHATNER: Is it possible that Admiral Byrd
saw an entrance to Inner Earth at the North Pole?
Almost a century after his alleged discovery,
there's no way to know for sure.
But modern science is trying to solve
this centuries-old mystery by conducting seismic studies
of the interior of the planet.
One of the pieces of data that was really earthshaking
was when Washington University published the discovery
of another ocean underneath the crust of the Atlantic Ocean.
They could actually read the waves crashing on a shore
on the inside of the crust.
That was really quite remarkable.
When I see reports like that, it leads me to believe,
at least, that there's a possibility
that we have a Hollow Earth.
If we gather evidence to prove
that our planet is actually hollow,
it could change everything.
Maybe the ancients were right all along.
Does the Earth really have enormous hollow expanses
beneath its surface? (chuckles)
It's a wild thought to consider, but one way or another,
we may soon find out the answer.
Because according to some, the future of humanity lies
not on the surface of the planet
but rather deep underground.
SHATNER: On the surface, this remote town
which is located in a harsh sandstone desert,
looks like a normal rural community.
But appearances can be deceiving,
because as it turns out,
most of the town is located underground.
Beneath the surface of Coober Pedy
lies a subterranean world,
complete with homes that are known as "dugouts"
and other living necessities.
Coober Pedy is-is an incredible town in the Australian Outback.
You go down these ramps into an underground space,
and then, you start seeing restaurants,
hotels,
people's houses,
churches underground.
All of this stuff excavated from this soft but very firm rock.
SHATNER: What would possess people
to live in such an unusual, underground community?
Well, the history of subterranean living
in Coober Pedy dates back to 1915,
when miners first traveled to this area
to dig for gold and precious opals.
GARRETT: The name for Coober Pedy comes from Aboriginal people
that lived there when the first explorers came out.
Coober Pedy means "white man in a hole."
(laughs) 'Cause they saw these people
digging into these things and disappearing into the Earth.
And of course, were confounded, like,
"Why do you keep going in there?
What do you want in this place?"
(machinery whirring)
SHATNER: Today, Coober Pedy is more famous
for being an alternative lifestyle community
than it is for opal mining.
According to recent estimates,
there are 1,000 individual dugouts carved
into the rock at Coober Pedy,
and approximately 2,500 people
live and work here year-round.
SHATNER: But do residents of this unorthodox community
enjoy their subterranean existence?
Well, if you ask the people of Coober Pedy,
they'll tell you they wouldn't want to live any other way.
SHATNER: While the story of Coober Pedy
and its residents is extraordinary,
some people believe that underground living
is not a matter of lifestyle preference
but rather, survival.
In recent years, an increasing number
of so-called "doomsday bunkers" have been built,
which are designed to protect residents
in the event of a catastrophe.
One of the most prominent of these subterranean shelters
is Vivos xPoint,
which is located in South Dakota.
Vivos xPoint is the largest survival community on Earth.
It was originally a government facility
that was in charge of munitions for World War II.
We have 575 bunkers
spread out across 7,000 acres,
or about nine square miles,
which is about half the size of Manhattan,
that are now being used for underground living and survival
in case of the worst possible events we might encounter.
People who live out there,
they're regular people like you and I.
And they come from all different walks of life.
I think it always pays to be prepared
to survive whatever may come.
GARRETT: If we think about
bunkers that are being built around the world,
all of these spaces are connected
by a fundamental belief
that the underground is a space of protection.
So it completely makes sense,
because humanity has always sought the underground
to hide from a hostile environment.
In the future, will millions of people
actually live a subterranean existence?
It may seem unlikely,
but the truth is that humanity's fate
may indeed rely on what's deep underground.
For instance, there are places where people have drilled
two and a half miles beneath the surface of the Earth
in search of a rare and precious metal
that is critical to our survival.
Gold.
SHATNER: In this nation located between South Africa and Mozambique,
stands an ancient, stepped mountain canyon
known as Bomvu Ridge.
The Bomvu Ridge is significant because, according to experts,
it is the site of the oldest mine in history.
Radiocarbon dating, uh, shows evidence
that this place was mined 40, 50,000 years ago.
And 50,000 years later,
the place is still producing iron today.
So, the history of the human species,
from the Stone Age to the digital age,
has this relationship to going after the metals
that we need at that particular place.
SHATNER: It's astonishing to think that, from the humble beginnings
of the first mine at Bomvu Ridge,
there are now more than 6,000 active mines
located all over the world.
Some of today's mines extend incredibly deep into the Earth,
such as the Mponeng gold mine in South Africa,
which reaches an astonishing
two and a half miles underground.
Every year, more than 3.2 billion tons of iron,
gold, silver, platinum and other precious metals
are extracted from our planet.
Today, we rely on mining perhaps even more
than our ancestors did,
because modern electronics depend on what are referred to
as rare earth elements.
KLINGER: The term "rare earths"
refers to 17 chemically similar elements
that have fantastic magnetic and conductive properties.
They are called things like europium,
lanthanum, praseodymium, cerium,
and together they are absolutely essential
for life as we know it today.
We need these elements for medical technologies,
communications, computer hardware.
But eventually, rare earth elements
are going to peter out.
And the real question is,
how deep will we go into the Earth
to get the elements that we need?
I think the simple answer to that is we will go
as far as our technologies allow us to go.
SHATNER: Will the Earth's supply of rare metals eventually run out?
It appears the only way to find out
is to keep digging into our planet,
in search of both essential resources
and also answers
to the many mysteries that lie beneath our feet.
GARNERO: As humans, we share
this curiosity,
this desire to understand what's beneath our feet.
And we want to explore.
We want to follow the breadcrumbs
of this mystery of what is down there.
COLLINS: Geophysical research
is revealing cave systems, caverns,
and obviously, whole cities
that were never known about in the past.
And we are going to discover
incredible things beneath the Earth in the future
that we could not even have imagined existing before.
There is something that compels humanity to explore underground,
whether we're looking for precious metals
or building new living spaces
or simply satisfying our desire to descend into the unknown.
And just like our ancestors before us,
we'll keep digging in search of all the subterranean secrets
held by our planet that, for now, remain...
...unexplained.
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