Underground Marvels (2019–…): Season 2, Episode 2 - Grand Canyon's Lost Treasure - full transcript
Exploring inside the Grand Canyon Caverns - North America's largest dry cave system. Plus, Cold War radar bunkers around the UK.
[dramatic music playing]
[narrator] On historic Route 66
lies the entrance to
a network of deep caves,
the largest dry caverns
in North America.
But how much more
remains undiscovered?
[John] The caves always
provides you another new question.
We haven't found a dead-end yet.
[narrator] Thousands
of miles away,
this subterranean radar system
gave the UK an edge
during the Cold War.
How did this extensive network keep
the country safe from nuclear threats?
[Mike] It was common
knowledge it was here.
What actually went on inside
was more the secret bit.
[narrator] And this ancient
underground fortress in Eastern Europe
provided military and religious
protection for hundreds of people.
How was this extensive
cave city constructed
almost 1,000 years ago?
[narrator] Throughout history, life
underground has captured our imagination.
It creates very frightening but
also a very beautiful experience.
[narrator] Now, we're
taking you further and deeper.
There's all kinds of wild theories
about what could be below.
[narrator] To unearth
the mysteries, the secrets
and the wonders of these...
Underground Marvels.
[intense music playing]
In Arizona, just east
of the Mojave desert
lies the entrance
to a little known
subterranean world.
Descending more than 200 feet into the
bedrock is a vast and mysterious cave network,
unmapped,
and largely undiscovered
until the 20th century.
Pre-dating the Grand Canyon
by more than 20 million years,
untold treasures are hidden
within its walls from across the ages.
[John] During the excavation, a
complete skeletal set was found there.
He was stupefied to realize
he'd found a gold mine.
[narrator] Their mysteries
are still being unraveled.
We'll be hiking in complete darkness
with nothing but our head lamps on.
[narrator] In 1927,
a woodcutter named Walter Peck
was riding his horse
to a poker game
when he almost fell into a
concealed hole in the ground.
His horse refused to go
any further along this trail,
in the dark on a moonless night.
His horse was smart enough not
to drop him 225 feet into the ground.
Walter came back the next day with a
lantern and being lowered in by his buddies
to realize he had found
a great big cavern.
This is the original location
that Walter Peck found in 1927.
I'm standing right on top
of the metal doors
that lead down to a series of
ladders and switchback stairs
that was used
all the way until 1962.
[narrator]
As he peered inside,
Peck was stunned by just how
far into the Earth he could see.
From the time his feet
touched the ground,
Peck thought he had struck gold.
Eager to start mining and
sensing a change in his fortunes,
Walter borrowed money to lease
the 600 acres of land above the caves.
Walter came down on
that first day with his lantern
and he got over here
to this wall,
was stupefied to realize
he had found a gold mine.
Turned out he hadn't.
[narrator] There was no gold
in these caves.
All he had was iron oxide, and a wonderful,
a great, big, giant hole in the ground.
[narrator] But Peck
was just beginning to realize
how unique this cavern system
would turn out to be.
[John] We're in the Halls of
Gold. It has 90-foot ceilings.
There are other big rooms, but
they're nowhere near as big as these.
It's just a magnificent
cathedral-like space.
[narrator] Understanding what
created these magnificent caves
reveals something unexpected.
While 97% of the world's caves are
still in the process of being formed,
with water actively cutting
new channels through them,
this cave system
is incredibly unusual.
Today, these caves are bone-dry.
Frozen in time,
essentially unchanged since the
water table dropped millions of years ago.
Geologist Paul Jorgensen began
studying and mapping the dry caves in 1993,
looking for evidence
of how they were formed.
Grand Canyon Caverns is in
the Mississippian limestone,
so it puts it at about
323 to 360 million years.
So it's a very ancient
limestone.
[dramatic music playing]
[narrator]
During its formation,
the limestone cavern
was submerged underwater.
The caverns were made from
water flowing from down below up
and eating away at the limestone
and creating the vast chambers
over many millions of years.
[narrator] Volcanic activity released
sulfuric acid that swirled among the rocks.
[Paul] The sulfuric acid was
going up the wall here, as a column,
and eroding away the rock,
smoothing all of the rough
edges, creating these scallops.
It's very similar to what you'd
have in a beach setting or a stream.
This later stuff here was
formed as the cave dried out.
So the water table dropped and
this other stuff was able to get in
as it was, uh, what we
call an aerial deposition.
So there was little tiny particles of
moisture that had the calcium in it,
and was able to stick on here.
[narrator] Paul's scientific
research has revealed some bizarre
atmospheric patterns
in the cavern's air flow.
Particularly in the area
known as Mystery Hill.
The mystery as to where
the air goes in the caverns.
We have air exchange
from the surface.
High pressure blows air in, low
pressure in the cave breathes out.
Today, the cave is breathing out
because the humidity
is high here.
We are looking at 60%.
Earlier in the day, it was at 50%.
We're on the top of a hill. There's
no water, there's no lakes, no streams.
So where is the water coming
from, where is the moisture?
That's a really good question.
There's all kinds of wild theories
about what could be below.
It could be a lake or a pond or
something that's holding water.
So it's a mystery for us.
Hope that we break into
a ceiling passage
and we have to get a boat
to go across it.
[suspenseful music playing]
[narrator] Today, geologists like Paul are
still searching for clues within the rock.
But back in the early 1900s, Peck was
more interested in pulling in crowds...
to marvel at the strange
subterranean world.
[John] This is
the original entrance.
From 1927 until about 1936,
it was the dope-on-a-rope.
They tied a rope around your waist
and lowered you down with a lantern.
You can explore as far as you
wanted to go, but at some point,
you yanked on the rope and
hopefully, they were paying attention,
and they pulled you up.
[narrator] Peck was determined
not to lose money on his investment
and he devised an even more
exciting opportunity to reel in visitors.
[John] In one of Walter's earliest
journeys, he found some bones
on a ledge about 40 feet down
from the natural entrance.
Walter, being
a marketing genius in a way,
quickly decided that those
bones must belong to cavemen.
[narrator] People came
from miles around
to see where cavemen had lived.
The tourist attraction here
was absolutely crazy.
More sales tax here than the
Grand Canyon National Park.
And the biggest money-maker
in the state of Arizona.
[narrator] But the bodies
weren't early humans,
and Peck never really thought
they were, so he kept it quiet.
But there had been
a saddle for a horse
lying next to the bones
when he found them.
[intense music playing]
The remains were later tested and
confirmed to be Hualapai Native Americans
who had died of the flu in 1918.
[John] It turned out that the
Hualapai had used the ledge
as a temporary morgue
in the winter,
and that some remains
had been left there.
[narrator] These caves had
actually been known and used
by the Hualapai people
for centuries.
[John] Hualapai really
objected to this route
because it went through what
they considered a sacred ledge.
[narrator] The accurate identification
of the bodies hurt Peck's publicity.
Had Peck's luck run out?
Or could a mysterious change of fortune
help him reinvent the Grand Canyon Caverns?
[dramatic music playing]
[narrator] As the Great Depression of
the 1930s took hold all over America,
President
Franklin D. Roosevelt
established the
Civilian Conservation Corps,
a program to give
state-funded work
to the millions of unemployed
across the US.
One of their first projects
in Arizona
was to build a new entrance
to the Grand Canyon Caverns.
The project was of particular interest
to the cave's owner, Walter Peck.
[John] Walter said, "I really
need a better way into my cave."
And so they built this
fantastic suspension bridge,
all of the materials of which are
from the building of Hoover Dam.
There's still concrete
on the side of the boards.
The cables are from
the Dam building itself.
It made it a lot easier with ladders
and switchback stairs at the top of this
for people to come down.
[narrator] The new entrance meant that
more people could enter the cave at a time.
Seeing
the financial opportunity,
Peck upped his prices
to 50 cents per person.
But the caves never made Peck
the millionaire he hoped to be.
And in 1957, he sold the land
to a family with a new vision.
The Ringsby family
sealed off this old entrance,
and they started
the new elevator route.
[narrator] The addition
of the elevator
allowed tourists to access parts of
the caves they never could before.
We're gonna go in the entrance
which is our original and natural entrance
into our first big room.
Welcome to our
Chapel of the Ages,
on the upper level
of our Caverns.
[narrator] And for the more
adventurous, Chris Cadlets
is in charge of leading
extreme cavern tours.
We'll be hiking in complete darkness
with nothing but our headlamps on.
[narrator] Taking visitors to
unchartered sections of the caves.
[Chris] Wild Tours gives guests
the opportunity to go off trail
and do some real caving in places
where very few people have been before.
[narrator] Chris takes an
active role in the exploration work
carried out
by geologist Paul Jorgensen.
Seeing how much Paul and the rest of the
cavers have found over the past 20 years
has really inspired, I think, a
whole younger generation of cavers
as to how much more there can
really be in this cave, you know.
Tons of cracks and crannies
riddled throughout the entire cave.
[Paul] Caves always provides
you another new question
until you get
to a total dead-end,
but we haven't
found the dead-end yet.
[narrator] Chris and Paul work
with other geologists and cavers
to map the rest of the system,
in hopes of discovering
new tunnels.
[Paul] We're looking to
find out where the air goes,
and why the air comes out back
moist again.
And that's where
the real excitement is.
If we were to find water,
we would likely then find life.
Life is paired with water, so
there's opportunities for new species
and all sorts of
exciting things.
[narrator] And life was exactly what
was found in 1958 by the Ringsby family.
[John] Right here during the
excavation for our stairway,
a complete skeletal set
was found.
[narrator] Just as Peck saw a marketing
hook with his claims about cave dwellers,
the Ringsbys optimistically declared
these bones to be from dinosaurs.
A whole new visitor center
was built,
complete with replica
dinosaurs adorning the roadway.
But just eight months after
the new facilities opened,
tests came back confirming that these
bones were not actually from dinosaurs.
[John] She was a 15-foot, 15,000
pound North American ground sloth.
And she ruled this area.
She was laying here
in the dirt right here.
She had fallen in the natural
entrance as many other creatures had.
After being here about 72 hours,
succumbed from dehydration,
and eventually turned into
just the skeletal remains.
[narrator] Once again, the owners
of the Grand Canyon Caverns
may have oversold
what actually lay within.
The claw marks have been
there the whole time we were here.
They say the sloth did the
claw marks trying to get out.
So the story is
a very heartfelt tale.
But just like some of
the other stories here,
we think they may have been
marketing-driven.
[narrator] The owners neither changed
the name from "Dinosaur Caves,"
nor got rid of
the dinosaur replicas.
They continued on
with their original story.
This was called "Dinosaur Caverns"
for quite a while in the 1970s,
when dinosaurs
were very popular.
There was a big dinosaur
craze around the United States.
There were never
any dinosaurs here.
[narrator] John McEnulty bought the
Caverns and surrounding land in 2000,
and decided to keep the dinosaurs as
a nod to the caves geological history.
John did, however, come up with
a few new attractions of his own.
I got a great idea to put
a dining spot down here.
And I found a spot which
I thought was perfect for it,
with our beautiful view
of the Hall of the Ages.
We don't do any cooking here,
everything is brought down from above,
from the restaurant
and the kitchen.
It makes a great place to eat.
[narrator] And if dining
underground isn't enough,
the caves offer another
one-of-a-kind experience
unlike anywhere else
in the world.
[John] This is our cavern suite.
It's a full mini-suite
64 meters underground.
We have 90-foot ceilings,
so it's a truly special place.
It can be difficult sleeping
down here sometimes
because you can hear
your heartbeat.
If we turn off all of our
lights here in the cave,
and all the lights here
in the cavern suite,
you won't be able to see
the hand in front of your face.
Within 40 seconds, your brain will be so
confused about what's up and what's down
that you'd no longer be able
to walk. You can barely crawl.
[narrator] This spectacular and unique
subterranean marvel of the Grand Canyon Caverns
may not be a gold mine,
but it is beyond rich in the
links to our prehistoric past.
[mystical music playing]
[narrator] At the height of the Cold
War, the world was on high alert.
As a nuclear strike
became more and more likely,
the British government developed
an elaborate plan to fight back.
What were these secret networks?
And how would they keep the country
safe should the unthinkable happen?
[dramatic music playing]
[narrator] As nations emerged
from a brutal Second World War,
they did so
in a very different reality.
A nuclear world.
Across the country,
Britain was bolstering itself
against a new enemy
in a Cold War,
and they headed below ground.
Nothing had been done like it
anywhere in the world.
[narrator] Dozens of innocuous-looking
buildings hide entrances
to what were once the nation's
most important secret network.
Every day, this was on alert.
[narrator] Equipped with the latest radar
system and large operational bunkers,
these layers were tough enough
to withstand a nuclear attack.
Higher pressure than outside meant
that any radiation that had got in here
couldn't get through
these doors.
[digital beeps]
[narrator] Perched on the Isle of
Portland on Britain's south coast
is a modest stone farm cottage
overlooking the English Channel.
Portland has been a military
island for hundreds of years.
Henry VIII actually built Portland
Castle to defend Portland harbor.
[narrator] It has sustained a
military presence ever since.
[sheep bleating]
[narrator]
This unassuming farmland
was the ideal location for a
top-secret Cold War installation,
providing around-the-clock
surveillance of the skies.
And dotted
around the countryside
are strange, unidentified
concrete buildings.
To protect the nation from
Russian military nuclear threats,
the British government developed
this advanced air defense radar system
code-named ROTOR.
[swan honking]
Su Illsley has run a farm on
the land for the last ten years.
All these concrete buildings, back in
the day of the ROTOR radar system
would've had rotary radars
mounted on the roofs.
They're now being used
as animal shelters.
[narrator] ROTOR stations
were radar look-out posts
linked to aboveground equipment
for scanning the skies
24 hours a day,
seven days a week.
[Su] When the ROTOR radar
systems were built around the country,
the threat to the UK from
Soviet Union was really real.
They wanted
an early warning system
for nuclear bombs from Russia.
[narrator] Su holds the key to one of
these vast subterranean military relics
lying forgotten
deep below her farm.
There's a 400-meter-long ROTOR
radar station bunker under the house.
Visitors that come to visit us at
the farm, and visit the animals,
they would have no idea what
they're actually walking above.
[narrator] Other than Su, few people have
ventured inside for more than 60 years.
There's no public access
to the bunker.
[narrator] Until today.
The first time that I came down here,
I just imagined that it wasn't very big.
Then you get further into the bunker
and you just see the immense scale.
This is the first time anyone's
been allowed down to film.
[suspenseful music playing]
These are the blast doors that would have
been closed to totally seal off the bunker.
This was the main control room.
I can imagine people sat at desks
with transponders, typewriters,
listening for signals,
looking at radar screens.
[narrator] Aboveground, the ROTOR radars
scan the sky for approaching threats.
[Su] They're connected
underground via cables
that sent the signals down all the
way back to the operations room.
[narrator] They were dug deep
down and disguised aboveground
so they didn't become
obvious strike targets.
Twenty-five ROTOR stations were
built all around the coast of the UK.
In Essex,
located 185 miles away,
is the site of another secret
ROTOR project bunker.
And this one had
an explosive purpose.
Every day, the Russians were
sending their Russian Bears over
to test our boundaries to see how
quickly we could scramble our aircraft.
Every day, this was on alert.
[narrator] Situated
on Britain's southern coast
was a top-secret first line of
defense during the Cold War.
Its sole purpose was to detect
approaching Russian bombers
and prevent
a nuclear Armageddon.
Kelvedon Hatch was the central
ROTOR station for Greater London,
and used as a regional
government headquarters.
If under a nuclear attack,
the bunker could hold hundreds
of military and civilian personnel
for up to three months.
In a mandatory
land acquisition deal,
the government bought the 25-acre
site from farmer Jim Parrish in 1952
to build a three-story
underground defense system.
[Mike] It was common knowledge
it was here.
What actually went on inside
was more the secret bit.
They told the locals that it was
an underground water reservoir.
[narrator] Jim's grandson, Mike Parrish,
has spent years restoring this ROTOR station
to operational condition.
The bunker
is built 125 feet underground,
and like the Portland bunker, its entrance
is through an ordinary-looking house.
[Mike] The ceiling
is two-foot thick concrete.
All the windows are shuttered
with metal shutters
and a big metal door.
When you're coming down the
road and looking up through the trees,
you can't even see this.
It was fairly secluded. They of
course got the compound around it.
The guards were here,
they had Alsatian dogs
protecting it.
[narrator] From within
the modest house,
the true scale of the underground
engineering becomes clear.
[Mike] If you've never
been here before,
you would be quite surprised,
probably, to see this long 120-yard tunnel.
It's constructed of concrete,
obviously, as the whole of the bunker is.
[narrator] Engineers designed this immense
structure to withstand a 25 kiloton bomb
half a mile away.
What you see here is the
ten-foot thickness of the walls.
These steel rods
are just reinforcing rods,
um, to make
the concrete stronger.
[narrator] It also needed
to survive the enormity
of a nuclear explosion.
They put sand and gravel so
we'd shake if a bomb would go off
rather than be solid.
They then put a mesh
around the outside
to protect the sensitive
equipment in here
from the electromagnetic pulse.
It wipes out anything
electrical.
[narrator] Should a bomb go off,
the bunker would absorb
the force of the explosion
in order to protect the doors.
[Mike] These are the blast
doors. They're quite hefty.
They each weigh about the
weight of a small family car.
Tunnel has done a dog-leg, and
that's so that the blast coming down it
would hit there and revert
back, and then hit here
before putting pressure
on the blast doors.
This is the main stairwell.
You can see that we're about a 100
foot underground where we're standing.
It's on three levels.
The bottom level has the
communications and the life support.
It was deemed to be the
safest, being the bottom,
so if everything collapsed
on it, this would still survive.
[narrator] Now closed off
from the world outside,
the ROTOR operators
could get to work
watching the skies
from under the ground.
This is the plotting floor.
There was a 24-foot
plotting table here
to identify where
the Russians were coming in.
[narrator] The primary threat was
the Tupolev Tu-95, code-named "Bear."
A large four-engine
turboprop-powered strategic bomber
and missile platform.
[Mike] You had to react quickly.
Every day, the Russians were
sending their Russian Bears over
to test our boundaries, to see how
quickly we could scramble our aircraft.
Every day, this was on alert.
[narrator] How the top-secret team tackled
their mission was rather surprising.
Triangulation team were fed
information from outside radio points
and they would have a table with a bit of
string and they would pull that string out
and lay it across that bearing
that they'd been given.
They'd get another bearing
from another radio station
and they'd pull out
a bit of string,
and hopefully
they got a third one.
That was where
the triangulation was,
that's where the aircraft were.
[narrator] Communication between the 25
ROTOR stations was of paramount importance.
[Mike] The teleprinter was the
main form of communication.
You typed your message, but
when it came out the other end,
it came out as a message
with holes punched,
and that was then fed into
a reader and printed out.
[narrator] This
communications network
connecting the stations
across the country
was way ahead of its time.
They had a system called
the chicken wire system.
If you wanted to talk from at
Horsham up to, say, Preston,
well, you'd do so via Coventry.
But if a bomb
had gone off on Coventry,
well, obviously,
you could make your way around
and still get to the same place.
[narrator] The prototype
communications network
would later provide the
infrastructure for the early Internet.
[Mike] We had that, the Americans
had it, the Europeans had it.
That's why the World Wide Web was
able to get up and running so quickly.
[narrator] The Cold War
became a catalyst
for an explosion
of technical innovation,
with each invention
outdoing the last.
The ROTOR system was built to spot
these missiles coming over from Russia,
and nothing had been done like it
ever before anywhere in the world.
[narrator] Civil defense
technology was evolving fast,
and the ROTOR project
couldn't keep up
with the Soviet Union's
nuclear capabilities.
Technology overtook
the ROTOR system.
It was the big white elephant
of its era.
[lilting music playing]
[Jarman] By the mid-1950s,
the more remote ROTOR outposts
like Portland
were becoming obsolete.
And soon, some of these
stations were forced to shut down.
[Mike] The ROTOR system
had a very short life.
It was slow and cumbersome.
By the time the information
had been received,
then sent it all off
to the airfields,
the Russians had traveled
at 500 miles an hour.
The whole ROTOR system throughout
the country closed down in 1959.
That wasn't because of lack
of threat from the Cold War,
it was because the system
just didn't work.
[narrator] However, the Kelvedon
Hatch station near London
remained fully operational
for nearly four decades,
only being decommissioned
in the 1990s.
So what became of this massive
military defense network?
And if nuclear war
did come knocking,
how do the engineers equip these
outposts to ensure locals were safe?
As civil defense technology
evolved in the mid-1950s,
the more remote ROTOR
outposts began to shut down,
but not all of them
were decommissioned.
The Kelvedon Hatch station
near London,
was converted into a regional
government headquarters
and renovated to accommodate
600 people for up to three months
in the event
of a nuclear strike.
[Mike] This is
the London bunker.
Had a bomb gone off, central
government wouldn't be able to govern.
They would have had life and
death decisions about their area.
[narrator] If under attack, engineers
had come up with a unique solution
to ensure the safety
of the occupants.
[Mike] If there was
a nuclear attack,
the blast doors would be shut,
the air would then
be going into the bunker
and maintaining the bunker
at a positive pressure.
Higher pressure than outside.
That meant that any radiation
that had got in here
couldn't get through these doors
because, obviously, it's being
repelled by the higher pressure.
[narrator] Engineers also designed a
way to ensure that the people inside
had access to clean air
after a nuclear blast.
Fresh air is coming through
an air vent behind us there.
And normally,
that fan over there is going.
And that then pumps the
fresh air into the bunker.
If the bomb had gone off, though,
then that fan would have been shut off,
and this one here switched on.
And this one is connected to the
nuclear biological and chemical filters.
[captivating music playing]
[narrator] Not only was the bunker
designed to keep people safe,
but it was equipped to meet
basic human needs.
This is one of the dormitories.
400 to 600 people down here.
Obviously, you got 600,
three shifts, you need 200 beds.
And so, they used
the hot bed system,
just like you do in submarines.
One man got out and the
next man got straight in.
[captivating music playing]
[narrator] Sleeping wasn't the only
necessity that had to be planned for.
What happened
when nature called?
[Mike] Below this concrete
floor, there's a large tank
that all the sewage flows into.
And the compressor keeps
the tank full of pressured air.
When the little tank is full of
sewage, it triggers the thing
and it blows it out the pipe
there marked "DS," dirty sewage,
and that then blows it
to the top of the bunker
where it then runs down by gravity
into the bespoke sewage fields.
[narrator] Mammoth underground
bunkers like Portland and Kelvedon Hatch
were the height of technical
engineering at their conception.
Today, ROTOR stations
are unique reminders
of the threat
of global annihilation
that the Cold War created
for more than three decades.
[intense music playing]
[narrator] Deep in the Caucasus
Mountains of Georgia, in Eastern Europe,
looms an enormous network
of artificial caves and tunnels.
Nearly 1,000 years old
and reaching 19 stories high,
Vardzia is an enormous complex
carved entirely by hand
during Georgia's golden age.
What secrets does
this labyrinth still hold?
What disastrous events
led to its abandonment?
[Mikheil speaking]
[narrator] And who has now moved
into the hidden passageways...
[bell tolling]
that make up
this imposing fortress?
[intriguing music playing]
[narrator] In the late
12th century,
as most of Western Europe
languished through medieval times,
the nation of Georgia
was coming of age.
Previously a fractured and
divided series of small territories,
they had been united
into a single kingdom.
Georgia was
in a unique position.
Located at the crossroads
of Europe and Asia,
it served as the eastern edge
of the Christian world,
and it needed robust defenses
to protect its country
and its faith.
So, their ruler and founder,
King George lll,
ordered an outpost to be built on
the southeast edge of the country...
on a site where cave dwellings
had existed since the 5th century
on the River Kura.
[narrator]
The Caucasus Mountains
run the length of the northern
Georgian border
from the Black Sea in the west
to the Caspian Sea in the east.
The same tectonic fault line
that created the Caucasus range
also deposited ash and minerals,
forming two types of rock.
Hard breccia on top,
and soft volcanic tuff.
[Mikheil speaking]
[narrator] Mikheil Elashvili
is a geophysicist
studying the structure
and stability of Vardzia.
[Mikheil speaking]
[narrator] Tiko Maisuradze is a
historian specializing in Vardzia
and the geopolitical era
during which it was built.
[Tiko speaking]
[narrator] The founder and
ruler of the newly unified country,
King George lll,
took a handful
of scattered caves
and expanded it
into a 400-room network
of underground passageways,
for both military
and religious purposes.
When King George died,
supervision of construction
fell to his daughter, Tamar.
Tamar became an influential
and celebrated ruler,
recorded in Georgian history
as King Tamar the Great.
Her first task as ruler
was to construct the huge
cavernous Church of Dormition
in the center of the complex.
[Tiko speaking]
[narrator] King Tamar expanded
the number of churches
and turned the eastern half of
the complex into a monastery.
[Tiko speaking]
[praying in foreign language]
[narrator] The community of religious
and military residents was bustling.
And the cave city now had
a large population to support.
[Tiko speaking]
[dramatic music playing]
[Tiko continues speaking]
[narrator] When it came to
providing fresh water for the complex,
the architects
didn't have to worry.
[Tiko speaking]
[narrator]
But after 300 years,
this thriving military
and religious community
would meet an unlikely end.
Its modern-day appearance
provides a clue to its ultimate downfall.
[narrator] By
the 12th and 13th century,
Vardzia was a thriving
underground community.
But its modern-day appearance
offers clues to its demise.
[Mikheil speaking]
[narrator] The earthquake
wiped out most of the citadel,
leaving many of the surviving
rooms in the complex exposed.
The monks continued to
live here for another century.
But further political upheaval
led to the site being abandoned
for several hundred years
until an unlikely rescuer
came to the city's aid.
[Mikheil speaking]
[narrator] Georgia was a
vital member of the Soviet Bloc.
Recognizing the city's
cultural importance,
Soviet archeologists
began restoring its remains.
[Mikheil speaking]
[narrator] Despite
their best efforts,
Vardzia continued to crumble.
[Mikheil speaking]
[narrator] Mikheil and his team
are now using modern techniques,
such as rock bolts and wire mesh
to ensure that Vardzia
doesn't deteriorate further.
- [rock breaking]
- [climber grunting]
[Mikheil speaking]
[narrator] Most of the site
is stable for now.
But making sure
it stays that way
is Mikheil's biggest challenge.
[Mikheil speaking]
[narrator] Vardzia
is once again under threat.
[Mikheil speaking]
[narrator] But Mikheil
and his team
have the latest monitoring
technology available,
including a ground radar system.
[Mikheil speaking]
[narrator] The team has
sufficiently stabilized the rock
for Vardzia's Russian Orthodox
monks to live here again.
These geophysicists
are hopeful that ongoing research
will allow future generations
to continue learning
about Georgia's rich history
in this magnificent structure.
[narrator] On historic Route 66
lies the entrance to
a network of deep caves,
the largest dry caverns
in North America.
But how much more
remains undiscovered?
[John] The caves always
provides you another new question.
We haven't found a dead-end yet.
[narrator] Thousands
of miles away,
this subterranean radar system
gave the UK an edge
during the Cold War.
How did this extensive network keep
the country safe from nuclear threats?
[Mike] It was common
knowledge it was here.
What actually went on inside
was more the secret bit.
[narrator] And this ancient
underground fortress in Eastern Europe
provided military and religious
protection for hundreds of people.
How was this extensive
cave city constructed
almost 1,000 years ago?
[narrator] Throughout history, life
underground has captured our imagination.
It creates very frightening but
also a very beautiful experience.
[narrator] Now, we're
taking you further and deeper.
There's all kinds of wild theories
about what could be below.
[narrator] To unearth
the mysteries, the secrets
and the wonders of these...
Underground Marvels.
[intense music playing]
In Arizona, just east
of the Mojave desert
lies the entrance
to a little known
subterranean world.
Descending more than 200 feet into the
bedrock is a vast and mysterious cave network,
unmapped,
and largely undiscovered
until the 20th century.
Pre-dating the Grand Canyon
by more than 20 million years,
untold treasures are hidden
within its walls from across the ages.
[John] During the excavation, a
complete skeletal set was found there.
He was stupefied to realize
he'd found a gold mine.
[narrator] Their mysteries
are still being unraveled.
We'll be hiking in complete darkness
with nothing but our head lamps on.
[narrator] In 1927,
a woodcutter named Walter Peck
was riding his horse
to a poker game
when he almost fell into a
concealed hole in the ground.
His horse refused to go
any further along this trail,
in the dark on a moonless night.
His horse was smart enough not
to drop him 225 feet into the ground.
Walter came back the next day with a
lantern and being lowered in by his buddies
to realize he had found
a great big cavern.
This is the original location
that Walter Peck found in 1927.
I'm standing right on top
of the metal doors
that lead down to a series of
ladders and switchback stairs
that was used
all the way until 1962.
[narrator]
As he peered inside,
Peck was stunned by just how
far into the Earth he could see.
From the time his feet
touched the ground,
Peck thought he had struck gold.
Eager to start mining and
sensing a change in his fortunes,
Walter borrowed money to lease
the 600 acres of land above the caves.
Walter came down on
that first day with his lantern
and he got over here
to this wall,
was stupefied to realize
he had found a gold mine.
Turned out he hadn't.
[narrator] There was no gold
in these caves.
All he had was iron oxide, and a wonderful,
a great, big, giant hole in the ground.
[narrator] But Peck
was just beginning to realize
how unique this cavern system
would turn out to be.
[John] We're in the Halls of
Gold. It has 90-foot ceilings.
There are other big rooms, but
they're nowhere near as big as these.
It's just a magnificent
cathedral-like space.
[narrator] Understanding what
created these magnificent caves
reveals something unexpected.
While 97% of the world's caves are
still in the process of being formed,
with water actively cutting
new channels through them,
this cave system
is incredibly unusual.
Today, these caves are bone-dry.
Frozen in time,
essentially unchanged since the
water table dropped millions of years ago.
Geologist Paul Jorgensen began
studying and mapping the dry caves in 1993,
looking for evidence
of how they were formed.
Grand Canyon Caverns is in
the Mississippian limestone,
so it puts it at about
323 to 360 million years.
So it's a very ancient
limestone.
[dramatic music playing]
[narrator]
During its formation,
the limestone cavern
was submerged underwater.
The caverns were made from
water flowing from down below up
and eating away at the limestone
and creating the vast chambers
over many millions of years.
[narrator] Volcanic activity released
sulfuric acid that swirled among the rocks.
[Paul] The sulfuric acid was
going up the wall here, as a column,
and eroding away the rock,
smoothing all of the rough
edges, creating these scallops.
It's very similar to what you'd
have in a beach setting or a stream.
This later stuff here was
formed as the cave dried out.
So the water table dropped and
this other stuff was able to get in
as it was, uh, what we
call an aerial deposition.
So there was little tiny particles of
moisture that had the calcium in it,
and was able to stick on here.
[narrator] Paul's scientific
research has revealed some bizarre
atmospheric patterns
in the cavern's air flow.
Particularly in the area
known as Mystery Hill.
The mystery as to where
the air goes in the caverns.
We have air exchange
from the surface.
High pressure blows air in, low
pressure in the cave breathes out.
Today, the cave is breathing out
because the humidity
is high here.
We are looking at 60%.
Earlier in the day, it was at 50%.
We're on the top of a hill. There's
no water, there's no lakes, no streams.
So where is the water coming
from, where is the moisture?
That's a really good question.
There's all kinds of wild theories
about what could be below.
It could be a lake or a pond or
something that's holding water.
So it's a mystery for us.
Hope that we break into
a ceiling passage
and we have to get a boat
to go across it.
[suspenseful music playing]
[narrator] Today, geologists like Paul are
still searching for clues within the rock.
But back in the early 1900s, Peck was
more interested in pulling in crowds...
to marvel at the strange
subterranean world.
[John] This is
the original entrance.
From 1927 until about 1936,
it was the dope-on-a-rope.
They tied a rope around your waist
and lowered you down with a lantern.
You can explore as far as you
wanted to go, but at some point,
you yanked on the rope and
hopefully, they were paying attention,
and they pulled you up.
[narrator] Peck was determined
not to lose money on his investment
and he devised an even more
exciting opportunity to reel in visitors.
[John] In one of Walter's earliest
journeys, he found some bones
on a ledge about 40 feet down
from the natural entrance.
Walter, being
a marketing genius in a way,
quickly decided that those
bones must belong to cavemen.
[narrator] People came
from miles around
to see where cavemen had lived.
The tourist attraction here
was absolutely crazy.
More sales tax here than the
Grand Canyon National Park.
And the biggest money-maker
in the state of Arizona.
[narrator] But the bodies
weren't early humans,
and Peck never really thought
they were, so he kept it quiet.
But there had been
a saddle for a horse
lying next to the bones
when he found them.
[intense music playing]
The remains were later tested and
confirmed to be Hualapai Native Americans
who had died of the flu in 1918.
[John] It turned out that the
Hualapai had used the ledge
as a temporary morgue
in the winter,
and that some remains
had been left there.
[narrator] These caves had
actually been known and used
by the Hualapai people
for centuries.
[John] Hualapai really
objected to this route
because it went through what
they considered a sacred ledge.
[narrator] The accurate identification
of the bodies hurt Peck's publicity.
Had Peck's luck run out?
Or could a mysterious change of fortune
help him reinvent the Grand Canyon Caverns?
[dramatic music playing]
[narrator] As the Great Depression of
the 1930s took hold all over America,
President
Franklin D. Roosevelt
established the
Civilian Conservation Corps,
a program to give
state-funded work
to the millions of unemployed
across the US.
One of their first projects
in Arizona
was to build a new entrance
to the Grand Canyon Caverns.
The project was of particular interest
to the cave's owner, Walter Peck.
[John] Walter said, "I really
need a better way into my cave."
And so they built this
fantastic suspension bridge,
all of the materials of which are
from the building of Hoover Dam.
There's still concrete
on the side of the boards.
The cables are from
the Dam building itself.
It made it a lot easier with ladders
and switchback stairs at the top of this
for people to come down.
[narrator] The new entrance meant that
more people could enter the cave at a time.
Seeing
the financial opportunity,
Peck upped his prices
to 50 cents per person.
But the caves never made Peck
the millionaire he hoped to be.
And in 1957, he sold the land
to a family with a new vision.
The Ringsby family
sealed off this old entrance,
and they started
the new elevator route.
[narrator] The addition
of the elevator
allowed tourists to access parts of
the caves they never could before.
We're gonna go in the entrance
which is our original and natural entrance
into our first big room.
Welcome to our
Chapel of the Ages,
on the upper level
of our Caverns.
[narrator] And for the more
adventurous, Chris Cadlets
is in charge of leading
extreme cavern tours.
We'll be hiking in complete darkness
with nothing but our headlamps on.
[narrator] Taking visitors to
unchartered sections of the caves.
[Chris] Wild Tours gives guests
the opportunity to go off trail
and do some real caving in places
where very few people have been before.
[narrator] Chris takes an
active role in the exploration work
carried out
by geologist Paul Jorgensen.
Seeing how much Paul and the rest of the
cavers have found over the past 20 years
has really inspired, I think, a
whole younger generation of cavers
as to how much more there can
really be in this cave, you know.
Tons of cracks and crannies
riddled throughout the entire cave.
[Paul] Caves always provides
you another new question
until you get
to a total dead-end,
but we haven't
found the dead-end yet.
[narrator] Chris and Paul work
with other geologists and cavers
to map the rest of the system,
in hopes of discovering
new tunnels.
[Paul] We're looking to
find out where the air goes,
and why the air comes out back
moist again.
And that's where
the real excitement is.
If we were to find water,
we would likely then find life.
Life is paired with water, so
there's opportunities for new species
and all sorts of
exciting things.
[narrator] And life was exactly what
was found in 1958 by the Ringsby family.
[John] Right here during the
excavation for our stairway,
a complete skeletal set
was found.
[narrator] Just as Peck saw a marketing
hook with his claims about cave dwellers,
the Ringsbys optimistically declared
these bones to be from dinosaurs.
A whole new visitor center
was built,
complete with replica
dinosaurs adorning the roadway.
But just eight months after
the new facilities opened,
tests came back confirming that these
bones were not actually from dinosaurs.
[John] She was a 15-foot, 15,000
pound North American ground sloth.
And she ruled this area.
She was laying here
in the dirt right here.
She had fallen in the natural
entrance as many other creatures had.
After being here about 72 hours,
succumbed from dehydration,
and eventually turned into
just the skeletal remains.
[narrator] Once again, the owners
of the Grand Canyon Caverns
may have oversold
what actually lay within.
The claw marks have been
there the whole time we were here.
They say the sloth did the
claw marks trying to get out.
So the story is
a very heartfelt tale.
But just like some of
the other stories here,
we think they may have been
marketing-driven.
[narrator] The owners neither changed
the name from "Dinosaur Caves,"
nor got rid of
the dinosaur replicas.
They continued on
with their original story.
This was called "Dinosaur Caverns"
for quite a while in the 1970s,
when dinosaurs
were very popular.
There was a big dinosaur
craze around the United States.
There were never
any dinosaurs here.
[narrator] John McEnulty bought the
Caverns and surrounding land in 2000,
and decided to keep the dinosaurs as
a nod to the caves geological history.
John did, however, come up with
a few new attractions of his own.
I got a great idea to put
a dining spot down here.
And I found a spot which
I thought was perfect for it,
with our beautiful view
of the Hall of the Ages.
We don't do any cooking here,
everything is brought down from above,
from the restaurant
and the kitchen.
It makes a great place to eat.
[narrator] And if dining
underground isn't enough,
the caves offer another
one-of-a-kind experience
unlike anywhere else
in the world.
[John] This is our cavern suite.
It's a full mini-suite
64 meters underground.
We have 90-foot ceilings,
so it's a truly special place.
It can be difficult sleeping
down here sometimes
because you can hear
your heartbeat.
If we turn off all of our
lights here in the cave,
and all the lights here
in the cavern suite,
you won't be able to see
the hand in front of your face.
Within 40 seconds, your brain will be so
confused about what's up and what's down
that you'd no longer be able
to walk. You can barely crawl.
[narrator] This spectacular and unique
subterranean marvel of the Grand Canyon Caverns
may not be a gold mine,
but it is beyond rich in the
links to our prehistoric past.
[mystical music playing]
[narrator] At the height of the Cold
War, the world was on high alert.
As a nuclear strike
became more and more likely,
the British government developed
an elaborate plan to fight back.
What were these secret networks?
And how would they keep the country
safe should the unthinkable happen?
[dramatic music playing]
[narrator] As nations emerged
from a brutal Second World War,
they did so
in a very different reality.
A nuclear world.
Across the country,
Britain was bolstering itself
against a new enemy
in a Cold War,
and they headed below ground.
Nothing had been done like it
anywhere in the world.
[narrator] Dozens of innocuous-looking
buildings hide entrances
to what were once the nation's
most important secret network.
Every day, this was on alert.
[narrator] Equipped with the latest radar
system and large operational bunkers,
these layers were tough enough
to withstand a nuclear attack.
Higher pressure than outside meant
that any radiation that had got in here
couldn't get through
these doors.
[digital beeps]
[narrator] Perched on the Isle of
Portland on Britain's south coast
is a modest stone farm cottage
overlooking the English Channel.
Portland has been a military
island for hundreds of years.
Henry VIII actually built Portland
Castle to defend Portland harbor.
[narrator] It has sustained a
military presence ever since.
[sheep bleating]
[narrator]
This unassuming farmland
was the ideal location for a
top-secret Cold War installation,
providing around-the-clock
surveillance of the skies.
And dotted
around the countryside
are strange, unidentified
concrete buildings.
To protect the nation from
Russian military nuclear threats,
the British government developed
this advanced air defense radar system
code-named ROTOR.
[swan honking]
Su Illsley has run a farm on
the land for the last ten years.
All these concrete buildings, back in
the day of the ROTOR radar system
would've had rotary radars
mounted on the roofs.
They're now being used
as animal shelters.
[narrator] ROTOR stations
were radar look-out posts
linked to aboveground equipment
for scanning the skies
24 hours a day,
seven days a week.
[Su] When the ROTOR radar
systems were built around the country,
the threat to the UK from
Soviet Union was really real.
They wanted
an early warning system
for nuclear bombs from Russia.
[narrator] Su holds the key to one of
these vast subterranean military relics
lying forgotten
deep below her farm.
There's a 400-meter-long ROTOR
radar station bunker under the house.
Visitors that come to visit us at
the farm, and visit the animals,
they would have no idea what
they're actually walking above.
[narrator] Other than Su, few people have
ventured inside for more than 60 years.
There's no public access
to the bunker.
[narrator] Until today.
The first time that I came down here,
I just imagined that it wasn't very big.
Then you get further into the bunker
and you just see the immense scale.
This is the first time anyone's
been allowed down to film.
[suspenseful music playing]
These are the blast doors that would have
been closed to totally seal off the bunker.
This was the main control room.
I can imagine people sat at desks
with transponders, typewriters,
listening for signals,
looking at radar screens.
[narrator] Aboveground, the ROTOR radars
scan the sky for approaching threats.
[Su] They're connected
underground via cables
that sent the signals down all the
way back to the operations room.
[narrator] They were dug deep
down and disguised aboveground
so they didn't become
obvious strike targets.
Twenty-five ROTOR stations were
built all around the coast of the UK.
In Essex,
located 185 miles away,
is the site of another secret
ROTOR project bunker.
And this one had
an explosive purpose.
Every day, the Russians were
sending their Russian Bears over
to test our boundaries to see how
quickly we could scramble our aircraft.
Every day, this was on alert.
[narrator] Situated
on Britain's southern coast
was a top-secret first line of
defense during the Cold War.
Its sole purpose was to detect
approaching Russian bombers
and prevent
a nuclear Armageddon.
Kelvedon Hatch was the central
ROTOR station for Greater London,
and used as a regional
government headquarters.
If under a nuclear attack,
the bunker could hold hundreds
of military and civilian personnel
for up to three months.
In a mandatory
land acquisition deal,
the government bought the 25-acre
site from farmer Jim Parrish in 1952
to build a three-story
underground defense system.
[Mike] It was common knowledge
it was here.
What actually went on inside
was more the secret bit.
They told the locals that it was
an underground water reservoir.
[narrator] Jim's grandson, Mike Parrish,
has spent years restoring this ROTOR station
to operational condition.
The bunker
is built 125 feet underground,
and like the Portland bunker, its entrance
is through an ordinary-looking house.
[Mike] The ceiling
is two-foot thick concrete.
All the windows are shuttered
with metal shutters
and a big metal door.
When you're coming down the
road and looking up through the trees,
you can't even see this.
It was fairly secluded. They of
course got the compound around it.
The guards were here,
they had Alsatian dogs
protecting it.
[narrator] From within
the modest house,
the true scale of the underground
engineering becomes clear.
[Mike] If you've never
been here before,
you would be quite surprised,
probably, to see this long 120-yard tunnel.
It's constructed of concrete,
obviously, as the whole of the bunker is.
[narrator] Engineers designed this immense
structure to withstand a 25 kiloton bomb
half a mile away.
What you see here is the
ten-foot thickness of the walls.
These steel rods
are just reinforcing rods,
um, to make
the concrete stronger.
[narrator] It also needed
to survive the enormity
of a nuclear explosion.
They put sand and gravel so
we'd shake if a bomb would go off
rather than be solid.
They then put a mesh
around the outside
to protect the sensitive
equipment in here
from the electromagnetic pulse.
It wipes out anything
electrical.
[narrator] Should a bomb go off,
the bunker would absorb
the force of the explosion
in order to protect the doors.
[Mike] These are the blast
doors. They're quite hefty.
They each weigh about the
weight of a small family car.
Tunnel has done a dog-leg, and
that's so that the blast coming down it
would hit there and revert
back, and then hit here
before putting pressure
on the blast doors.
This is the main stairwell.
You can see that we're about a 100
foot underground where we're standing.
It's on three levels.
The bottom level has the
communications and the life support.
It was deemed to be the
safest, being the bottom,
so if everything collapsed
on it, this would still survive.
[narrator] Now closed off
from the world outside,
the ROTOR operators
could get to work
watching the skies
from under the ground.
This is the plotting floor.
There was a 24-foot
plotting table here
to identify where
the Russians were coming in.
[narrator] The primary threat was
the Tupolev Tu-95, code-named "Bear."
A large four-engine
turboprop-powered strategic bomber
and missile platform.
[Mike] You had to react quickly.
Every day, the Russians were
sending their Russian Bears over
to test our boundaries, to see how
quickly we could scramble our aircraft.
Every day, this was on alert.
[narrator] How the top-secret team tackled
their mission was rather surprising.
Triangulation team were fed
information from outside radio points
and they would have a table with a bit of
string and they would pull that string out
and lay it across that bearing
that they'd been given.
They'd get another bearing
from another radio station
and they'd pull out
a bit of string,
and hopefully
they got a third one.
That was where
the triangulation was,
that's where the aircraft were.
[narrator] Communication between the 25
ROTOR stations was of paramount importance.
[Mike] The teleprinter was the
main form of communication.
You typed your message, but
when it came out the other end,
it came out as a message
with holes punched,
and that was then fed into
a reader and printed out.
[narrator] This
communications network
connecting the stations
across the country
was way ahead of its time.
They had a system called
the chicken wire system.
If you wanted to talk from at
Horsham up to, say, Preston,
well, you'd do so via Coventry.
But if a bomb
had gone off on Coventry,
well, obviously,
you could make your way around
and still get to the same place.
[narrator] The prototype
communications network
would later provide the
infrastructure for the early Internet.
[Mike] We had that, the Americans
had it, the Europeans had it.
That's why the World Wide Web was
able to get up and running so quickly.
[narrator] The Cold War
became a catalyst
for an explosion
of technical innovation,
with each invention
outdoing the last.
The ROTOR system was built to spot
these missiles coming over from Russia,
and nothing had been done like it
ever before anywhere in the world.
[narrator] Civil defense
technology was evolving fast,
and the ROTOR project
couldn't keep up
with the Soviet Union's
nuclear capabilities.
Technology overtook
the ROTOR system.
It was the big white elephant
of its era.
[lilting music playing]
[Jarman] By the mid-1950s,
the more remote ROTOR outposts
like Portland
were becoming obsolete.
And soon, some of these
stations were forced to shut down.
[Mike] The ROTOR system
had a very short life.
It was slow and cumbersome.
By the time the information
had been received,
then sent it all off
to the airfields,
the Russians had traveled
at 500 miles an hour.
The whole ROTOR system throughout
the country closed down in 1959.
That wasn't because of lack
of threat from the Cold War,
it was because the system
just didn't work.
[narrator] However, the Kelvedon
Hatch station near London
remained fully operational
for nearly four decades,
only being decommissioned
in the 1990s.
So what became of this massive
military defense network?
And if nuclear war
did come knocking,
how do the engineers equip these
outposts to ensure locals were safe?
As civil defense technology
evolved in the mid-1950s,
the more remote ROTOR
outposts began to shut down,
but not all of them
were decommissioned.
The Kelvedon Hatch station
near London,
was converted into a regional
government headquarters
and renovated to accommodate
600 people for up to three months
in the event
of a nuclear strike.
[Mike] This is
the London bunker.
Had a bomb gone off, central
government wouldn't be able to govern.
They would have had life and
death decisions about their area.
[narrator] If under attack, engineers
had come up with a unique solution
to ensure the safety
of the occupants.
[Mike] If there was
a nuclear attack,
the blast doors would be shut,
the air would then
be going into the bunker
and maintaining the bunker
at a positive pressure.
Higher pressure than outside.
That meant that any radiation
that had got in here
couldn't get through these doors
because, obviously, it's being
repelled by the higher pressure.
[narrator] Engineers also designed a
way to ensure that the people inside
had access to clean air
after a nuclear blast.
Fresh air is coming through
an air vent behind us there.
And normally,
that fan over there is going.
And that then pumps the
fresh air into the bunker.
If the bomb had gone off, though,
then that fan would have been shut off,
and this one here switched on.
And this one is connected to the
nuclear biological and chemical filters.
[captivating music playing]
[narrator] Not only was the bunker
designed to keep people safe,
but it was equipped to meet
basic human needs.
This is one of the dormitories.
400 to 600 people down here.
Obviously, you got 600,
three shifts, you need 200 beds.
And so, they used
the hot bed system,
just like you do in submarines.
One man got out and the
next man got straight in.
[captivating music playing]
[narrator] Sleeping wasn't the only
necessity that had to be planned for.
What happened
when nature called?
[Mike] Below this concrete
floor, there's a large tank
that all the sewage flows into.
And the compressor keeps
the tank full of pressured air.
When the little tank is full of
sewage, it triggers the thing
and it blows it out the pipe
there marked "DS," dirty sewage,
and that then blows it
to the top of the bunker
where it then runs down by gravity
into the bespoke sewage fields.
[narrator] Mammoth underground
bunkers like Portland and Kelvedon Hatch
were the height of technical
engineering at their conception.
Today, ROTOR stations
are unique reminders
of the threat
of global annihilation
that the Cold War created
for more than three decades.
[intense music playing]
[narrator] Deep in the Caucasus
Mountains of Georgia, in Eastern Europe,
looms an enormous network
of artificial caves and tunnels.
Nearly 1,000 years old
and reaching 19 stories high,
Vardzia is an enormous complex
carved entirely by hand
during Georgia's golden age.
What secrets does
this labyrinth still hold?
What disastrous events
led to its abandonment?
[Mikheil speaking]
[narrator] And who has now moved
into the hidden passageways...
[bell tolling]
that make up
this imposing fortress?
[intriguing music playing]
[narrator] In the late
12th century,
as most of Western Europe
languished through medieval times,
the nation of Georgia
was coming of age.
Previously a fractured and
divided series of small territories,
they had been united
into a single kingdom.
Georgia was
in a unique position.
Located at the crossroads
of Europe and Asia,
it served as the eastern edge
of the Christian world,
and it needed robust defenses
to protect its country
and its faith.
So, their ruler and founder,
King George lll,
ordered an outpost to be built on
the southeast edge of the country...
on a site where cave dwellings
had existed since the 5th century
on the River Kura.
[narrator]
The Caucasus Mountains
run the length of the northern
Georgian border
from the Black Sea in the west
to the Caspian Sea in the east.
The same tectonic fault line
that created the Caucasus range
also deposited ash and minerals,
forming two types of rock.
Hard breccia on top,
and soft volcanic tuff.
[Mikheil speaking]
[narrator] Mikheil Elashvili
is a geophysicist
studying the structure
and stability of Vardzia.
[Mikheil speaking]
[narrator] Tiko Maisuradze is a
historian specializing in Vardzia
and the geopolitical era
during which it was built.
[Tiko speaking]
[narrator] The founder and
ruler of the newly unified country,
King George lll,
took a handful
of scattered caves
and expanded it
into a 400-room network
of underground passageways,
for both military
and religious purposes.
When King George died,
supervision of construction
fell to his daughter, Tamar.
Tamar became an influential
and celebrated ruler,
recorded in Georgian history
as King Tamar the Great.
Her first task as ruler
was to construct the huge
cavernous Church of Dormition
in the center of the complex.
[Tiko speaking]
[narrator] King Tamar expanded
the number of churches
and turned the eastern half of
the complex into a monastery.
[Tiko speaking]
[praying in foreign language]
[narrator] The community of religious
and military residents was bustling.
And the cave city now had
a large population to support.
[Tiko speaking]
[dramatic music playing]
[Tiko continues speaking]
[narrator] When it came to
providing fresh water for the complex,
the architects
didn't have to worry.
[Tiko speaking]
[narrator]
But after 300 years,
this thriving military
and religious community
would meet an unlikely end.
Its modern-day appearance
provides a clue to its ultimate downfall.
[narrator] By
the 12th and 13th century,
Vardzia was a thriving
underground community.
But its modern-day appearance
offers clues to its demise.
[Mikheil speaking]
[narrator] The earthquake
wiped out most of the citadel,
leaving many of the surviving
rooms in the complex exposed.
The monks continued to
live here for another century.
But further political upheaval
led to the site being abandoned
for several hundred years
until an unlikely rescuer
came to the city's aid.
[Mikheil speaking]
[narrator] Georgia was a
vital member of the Soviet Bloc.
Recognizing the city's
cultural importance,
Soviet archeologists
began restoring its remains.
[Mikheil speaking]
[narrator] Despite
their best efforts,
Vardzia continued to crumble.
[Mikheil speaking]
[narrator] Mikheil and his team
are now using modern techniques,
such as rock bolts and wire mesh
to ensure that Vardzia
doesn't deteriorate further.
- [rock breaking]
- [climber grunting]
[Mikheil speaking]
[narrator] Most of the site
is stable for now.
But making sure
it stays that way
is Mikheil's biggest challenge.
[Mikheil speaking]
[narrator] Vardzia
is once again under threat.
[Mikheil speaking]
[narrator] But Mikheil
and his team
have the latest monitoring
technology available,
including a ground radar system.
[Mikheil speaking]
[narrator] The team has
sufficiently stabilized the rock
for Vardzia's Russian Orthodox
monks to live here again.
These geophysicists
are hopeful that ongoing research
will allow future generations
to continue learning
about Georgia's rich history
in this magnificent structure.