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A deadly majestic cavern.

Filled with razor sharp, treacherous giant crystals.

Official YIFY movies site: YTS.MX

Look at this.

This is way cool, huh?

Holy smokes.

Are there other marvels

that match its beauty and punishing heat?

- I love this place.

No matter how hard it is to work in here.

A team of scientists and

explorers risk their lives to find out.

Like the little thing in

the back of your mind saying go

check it out, go check it out.

They uncover other lethal stunning caverns.

They stumble upon an unexplored mystery

hidden deep beneath the surface of the Earth.

Hey guys, I got something.

45 degrees celsius.

90% humidity.

The crystal cave does not want you there.

It will kill you in a matter of minutes.

Yet there are people who are willing to risk

their lives to understand this

breathtaking, mysterious place.

The crystal caves, located in a

tiny Mexican mining town called Naica.

250 kilometers South of the US

border in the heart of Chihuahua.

Located 300 meters underground in

a colossal lead mine, the crystal cave

remained hidden for over half a million years.

Until it was accidentally discovered by miners in 2000.

Today, an organization called The Naica Project

studies and documents the cave.

Lead by Gonzalo Infante, the project has

perfected technology to help keep explorers alive.

They have developed specialized suits

and respirators that help keep humans

alive for up to 45 minutes in the deadly heat.

In 2008, a team of scientists and

explorers unlocked some of its mysteries.

I can't imagine once we get in there.

I can feel the temperature.

Two years later, another team

has come back for one final expedition.

- Guys, this is the entry point of this

beautiful cave that we are about to enter.

Only one side, breathe slowly.

The cave can kill

a human being in 30 minutes.

They're required to enter without

protective suits for just five

minutes to test their physical

limits in the deadly heat.

When you feel a little

with a blurry eyesight, or having a

little headache, even a small headache,

please tell me, I can take you out.

Safety is the most important thing in this cave.

The team is monitored

from Mission Control to see how they

react in their five minute exposure test.

- Your body is an amazing machine,

tells you everything, listen to it.

That's it guys.

Everyone okay?

All right?

- Come on, let's go.

Oh this is incredible!

Can you imagine what the guys

who discovered this must've thought?

Wow.

It is a visual marvel unlike any other.

I can't believe how hot they are.

It's incredible.

Look, it's all the way back there.

A gigantic crystal

cathedral created by nature, completely

defying our understanding of

what things on this planet look like.

An alien world.

Right here on Earth.

- Wow, I love these.

The cavern is the size of a

football field and about as high

as a two story building.

Some crystals are 11 meters long

and 55 tons, as high as telephone poles

and 100 times as heavy.

You know, what's amazing

is there's no small crystals.

All of these crystals are born big.

The team starts at the door.

Beyond it is what's called the forest.

A number of upright, pillar-like crystals.

Be careful.

They descend 15 meters to the

center of the cave where there is a deep

depression and the best view of the entire cavern.

I thought that they would be all

growing up from the floor, but all of these

guys in here are growing from every surface.

25 meters to their

right is a sheer crystal face.

At its top is a tiny passageway that

will be their main objective.

Wow, looks like ice.

It's incredible.

The 2008 team discovered

a crevasse that appeared to lead to another

crystal cave, but fail to penetrate it.

The new team will focus their efforts to see

if another majestic cavern awaits discovery.

- It's amazing that you can see

they're growing in every direction.

Apart from the goal of discovering

a new cave, the team believes their expedition

may even blaze the trail for a

better understanding of life on Earth.

Biologist Penny Boston is the only

team member who was on the 2008 expedition.

The first trip was a wonderful

experience to see an environment that

was really very different from what I

had seen before, but of course we came in

really not knowing how to approach a lot

of the things that we would want to do, and so we

got some very tantalizing and wonderful results.

This second trip of course is

to build on that.

Virologist Curtis Suttle brings

a team with a radical new idea.

To find ancient viruses that

have been trapped in the cave.

We think that Naica,

being quite an usual environment

with hot, subterranean water coming out

is quite an extreme environment.

We're interested in the search for

life on other planets and where they

may exist, and so one of the things that

we're fairly good at is finding lifeforms

that people didn't know existed before.

Before the scientists

begin their work, a new secondary

base camp will be built inside the cave.

It is called the ice cube.

The idea is to pump cool air into

a tent inside the cave to lengthen

mission time to up to two hours.

If it works, the ice cube is the team's

best weapon against the cave's deadly heat.

The scientists have learned that the

crystal cave is not the only marvel

buried beneath the Earth's surface.

They will examine other spectacular caverns in the mine.

Seeking proof that the giant crystal

cave is part of a larger system.

Perhaps hundreds of undiscovered wonders are here.

After four minutes in the cave,

their hearts are racing like after a

fast sprint, but will not slow down in the

heat as the organs scream for more oxygen.

Sweat does not evaporate from the skin, so they

are literally poaching in their own body heat.

After about half an hour, they would all be dead.

- All right, I think I've reached my limit.

Okay guys!

Watch your head, Victor.

Vital signs are taken.

If anyone gets a dangerous reading, they can be

banned from the cave for the day, or for good.

- I can feel my heart pounding in

all the blood vessels in my face.

I can feel...

.

As the explorers make their

plans in the hottest cave on Earth, others seek

to find another crystal cave from the surface.

Marc Beverly is a climber and rescuer.

He's brought a handpicked team of

explorers to investigate a 600 meter

deep hole in the desert.

The mine calls it the robin hole.

It's an eight foot wide ventilation

shaft that extends to the bottom of the mine.

Somewhere inside may lie another crystal

cave that no human being has ever explored.

In 2009, the mine drilled this

gigantic shaft to cool the hot tunnels below.

A camera attached to the drill bit

saw a cavern about 150 meters down.

The poor video showed what looked like a giant crystal.

Beverly's job is to figure out a way

to get down the robin hole to see if

another undiscovered crystal cave awaits.

I'm really excited to be part

of this whole process, I know my

team's excited to be part of this process.

To have a first descent and a first discovery

of a cave that's given to you on a silver

platter is unbelievable, people die for this.

It's just amazing.

That looks good, you guys.

Let's find a bar that fits through that.

Some kind of a EMT pipe or something,

we'll hang it, and then we'll just thread it.

From the surface the

robin hole doesn't look all that

impressive, but it goes 600 meters down.

Over one and a half times deeper

than the Empire State Building is tall.

Any fall spells certain death.

A surface base camp has been set up near the shaft.

A scientific team will work with Beverly's crew.

- Now these crystals, they form out of that

solution at a very specific temperature range.

Sarah Poirier is a space scientist.

She's here to study how humans

react in stressful environments.

To her, studying the cave is much like a space mission.

We know there's physical challenges,

but we also really need to be aware of the

psychological challenges involved with

putting humans in these extreme environments,

humans are the weakest link when we're exploring anywhere.

- And we're gonna come from above,

we're gonna hit the edge of the limestone,

and then hopefully we're going to see crystals.

Geologist Victor Torres

wants to help map the new caverns in an

effort to determine if the crystal cave is unique.

The crystals in the crystal

cave are huge, are born huge.

There's no interlacing of a bunch of little

crystals that grew together like normal

geodes, this is something collectively different.

The unexplored cave sits at

approximately the same depth as the crystal cave.

Is it possible that the two caves are connected?

The climbing team is determined to find out.

a long life .

Besides this shaft and the

crystal cave, the explorers will also examine

smaller spectacular caverns within the mine area.

A cave called The Cave of Swords.

Another, The Queen's Eye.

Finally, The Cave of Sails.

- Need some help?

The hunt is on.

Teams above ground and below the

surface now have clear missions.

There's danger at every turn.

There is one last twist.

The crystal cave may soon be underwater.

Half a million years ago, the crystals grew from

the size of a grain of salt to 50 ton monoliths.

They were formed under hundreds of

millions of gallons of scalding,

50 degree water heated from volcanic intrusions.

The same intrusions which now

give the cave its deadly heat.

Enormous pumps built by the mine

keep the cave dry at a rate of

four million liters per hour.

But in 2008, mine authorities indicated

that they might turn those pumps off.

- Okay, let's go.

- Okay.

Not only is this mission

dangerous, it could also be humanity's

last chance to explore this underground marvel.

Look at this!

This is way cool, huh?

Holy smokes.

For the scientists,

the question to unlock the cave's

secrets is now a race against time.

Ever since the cave was discovered,

the Naica project team sought

ways to lengthen mission time.

When they first arrived in 2005,

the was clear that the deadly heat

made exploration all but impossible.

They began designing suits to

protect them from the heat.

After years of risking trial and error,

they discover that wearing ice

close to the skin covered by insulated

suits was the most effective solution.

Respirators connected to ice filled

backpacks send cool air to the lungs.

- Oooh, nice.

The masks even protect the eyes

as eyeballs can scorch in the cave's heat.

- We know that in extreme condition,

only passive system can work.

filled of ice where there is a

flux of air around and you breathe

and the cool air goes on the eyes

in order not to burn the eyes.

Making ice in the

scorching hot mission control room

requires a customized freezer that

can make ice in half an hour.

Missions went from 10 to 15 minutes to up to

an hour, but the suits were bulky and heavy.

- Here he goes, it's just like a backpack.

- There we go.

Over time, designs became lighter,

but still weighing in at 20 kilograms.

The next problem was photography.

Most electronic technology fails in the

cave's extreme heat and humidity.

Several cameras were tested, all instantly fogged.

And moments later, died.

The Naica project team found a low tech solution.

Put the camera in a plastic bag for two

hours inside the cave to let it heat up.

When removed, equalized temperatures

mean minimal humidity on sensitive electronics.

But even after years of experience,

camera failures are common and catastrophic.

The team also developed a motion

controlled robotic camera which takes

thousands of stills over several

hours to create a moving image.

This simple device has captured

some of the cave's most stunning images.

The first mission on this 2009

expedition to the giant crystal

cave is to explore the mysterious

crevasse that has proven to be

the cavern's most deadly impasse.

Explorers believe it may lead to another crystal cave.

This crevasse also nearly took the life

of one of the original team's explorers.

In 2006, Tullio Bernabei entered

the cave with a cameraman to test

the suits and respirators.

As the two explore the cave, Tullio

decided to cross an impasse by himself

to investigate the crevasse.

He saw that the cave kept going, so he went in further.

Much further.

When it was time to head back, his respirator failed.

He was on his own.

No one could see him in the cave.

Without any cool air to breathe, Bernabei

didn't know if he could make the

30 meters back to the cave entrance.

He stumbled back to the cave entrance,

his brain nearly failing, his heart nearing

cardiac arrest from the punishing heat.

Bernabei barely escaped with his life.

This time, Naica project caver

Mario Corsolini will explore the same

crevasse that nearly killed Bernabei.

In his protective suit, he will have

45 minutes before his life is at risk.

To study the deadly passageway, the technical

team has created a remote camera arm.

It can look in places human beings can't.

And send high definition images

back to mission control for analysis.

Corsolini makes his way to the crevasse.

It takes about five minutes for

the experienced caver to climb the sheer

crystal of the upper reaches of the cave.

In a deadly place that is furthest

from the entrance and rescue.

The opening here looks like a shark's mouth.

Beyond it, a world only seen by a handful

of daring explorers and never filmed.

Corsolini steps into a dazzling

corridor lined with razor sharp crystals.

It's a disorienting maze-like place.

All jagged.

Yes.

They'll chew you up.

They'll chew you up good.

But it appears to be a tunnel.

He explores a series of tiny

passageways seeing another cavern.

The tunnel is five meters long,

two meters across, and lined with crystals.

At its end is a wall of crystals, that if it can

be climbed, appears to lead to a black void.

Another cave?

Scientists Victor Torres and Sarah Poirier

want to explore the new passageway

and test the limits of their equipment.

Sarah, come over here,

grab this one with your left hand.

Come up, foot here.

Yup.

And then here.

They discover just how

treacherous the climb to the crevasse is.

It's an obstacle course of jagged

crystals that can cut through skin.

This end here, up.

Broken and uneven crystals

on the cave floor means moving in

the heavy suits is all but impossible.

Good job.

In here?

Right up here, there, yeah.

.

Up here.

Finally the scientists reach the crevasse.

Hotter than The Sahara, more humid than The Amazon.

A deadly combination unlike any place on Earth.

50 degrees celsius and humidity near 100%.

Wow, oh my God, look at this!

This is way cool, huh?

Holy smokes.

Corsolini is all but exhausted.

Physical movement in this heat wearing a

20 kilogram suit is all his body can bear.

They can last just minutes longer.

Just long enough to get a sense

of an unexplored visual marvel

that may well be the passageway

to another crystal cave.

It appears to go on for about

five meters, and then opens up.

But to what?

Sarah, we need to go now.

Time is up.

The three explorers must now make

their way back to the control room.

- Gonna go this way, okay?

Yup.

- Foot here, move that way.

Yup.

- Then foot here.

They learn an important lesson.

To get to the crevasse, you have to

reserve enough energy to get back down.

- Can I take your hand?

Close.

Move now.

Yup.

The door is just 30 meters away.

It might as well be 500.

- I'm good.

It's a little hard to breathe

right now, but it's all right.

You okay?

- Yeah, I'm okay, I'm glad I'm out though.

I think it was at the right time, another minute

or two I would've been having problems.

In mission control,

Sarah Poirier's vital signs are closely monitored.

She's been pushed to the physical limit.

- Can we get a cold glass of water?

Here.

- Sarah, go slow with this, okay?

But she's seen with her

own eyes what the team came here to determine.

- Let's walk back there slowly,

if you feel dizzy, just hold on.

.

Thank you.

There's a tunnel up there.

Where it goes is the next deadly mystery to solve.

Inside the crystal cave, Victor Torres

decides to be the first to experiment

with the ice cube tent.

Cool air is being pumped into the tent.

The tech team estimated that it

should be about 35 degrees celsius.

Not exactly chilly, but lower than the

body's core temperature of 37 degrees.

But the ice cube isn't cooling down much.

Torres can feel a difference, but not

enough to bring his overheated

body back to safe levels.

For now, the ice cube is off limits.

Two years before this mission,

another team of scientists examin

the crystals to determine what they

are made of and how they grew so big.

These stunning pillars are made of gypsum,

the same mineral as common drywall.

But there's nothing common about these crystals.

They are five times larger than any previously discovered.

Gypsum takes a long time to grow into crystals

and needs constant conditions of water and heat.

The crystal cave was underwater for half a million

years until it was discovered by miners in 2000.

The water trapped in the cave was rich with gypsum.

The gypsum clung to the cave walls and floor.

Growing over time into the giant crystal cave.

But the mystery remains whether this

geological marvel is unique.

The scientists seek evidence that the

conditions may have been right for

other crystal caves to grow in this

cauldron buried beneath a Mexican dessert.

As the explorers finish the first stage

of their mission, Penny Boston and

colleague Mike Spildee ready for their own

treacherous venture into the cave's deadly heat.

Boston is looking for life where

no one would ever suspect life could survive.

One of the big surprises of

all of science really over the last

20 or 30 years is just how much life

there actually is in the subsurface.

What we're finding as a community

is that when we go into places

like Niaca or other deep environments,

whether they be mines or natural caves,

we're finding an astonishing array

of different kinds of microorganisms.

They have a lot to tell us about the

origin and evolution of life on the planet.

In 2008, Boston found

bacteria trapped in fluid inclusions, tiny air

pockets that formed when the crystals were growing.

She reanimated the bacteria, brought them back to life.

They were unlike anything else ever seen on Earth.

Her work sheds light on the existence

of life on other planets.

So these are low nutrient environments

and we're interested in the kinds of organisms

that can actually make their living not

using organic materials like you and I eat,

but chewing through bedrock and using inorganic

mineral compounds as their energy source.

Just keep it down like that when

you pull it out, then we'll light it.

It put my drill on fire, that can't be good.

Flaming drill.

Now she's trying again.

This time she wants to sample deeper

from a crystal with the aim to retrieve

a more complete sample of bacterial DNA.

What do you think?

Yeah, let's go for it.

- I think so.

The crystals are soft

as human fingernails, so easy to drill.

But that same softness can make it

hard to reach a fluid inclusion

without contaminating it.

- I can see water coming up into it.

Good.

Thing was a juicy one.

Good, this may work.

- All right, we're off.

The clock is ticking.

Finally, success.

- Perfect, love it.

The team makes their

way back towards mission control,

but it's clear Penny Boston has

pushed herself to the brink.

.

At first she seems okay.

We just pushed with a sterile .

We couldn't get the lighters to work.

We rubbed it off on crystal and then

got a flame.

We sterilized it, I thought we

were gonna have to come back out.

I was nearly in tears.

It was a complete failure.

Trying to get it open.

send you over the edge?

Yeah.

Penny Boston is the

team's most experienced caver.

It's a sobering lesson for the others

who are beginning to understand the deadly

risks of exploring this unforgiving cave.

- I shouldn't cry more, I'm wasting fluid.

The real dangers still lie ahead.

The crystal cave is in the center of

Chihuahua, a vast desert plateau

South at the border of Texas.

Naica is a tiny, isolated dot on the map.

Naica produces lead, copper, and silver.

About 5,000 people live in Naica.

The entire economy is driven by the mine.

And has been for over 100 years.

At the beginning of the 20th century,

100 years before the crystal cave was discovered,

another cavern in this mine complex

produced remarkable crystals that

now adorn museums around the world.

The cave is called The Cave of Swords.

Discovered in 1910, The Cave of Swords is located

closer to the mine entrance at about 120 meters.

Compared with the much deeper crystal cave at 300 meters.

Its names comes from the unique

dagger-like crystals on the cave walls.

These crystals are also selenite, or common gypsum.

But there is nothing else like them anywhere in the world.

They too grew underwater, but this

cave was not always flooded.

The scientists believe the water here rose and

fell over hundreds of thousands of years.

So the crystal did not grow as

large as those in the crystal cave.

These crystals also formed underwater under tremendous heat.

This cave produced a beauty quite unlike that

of the crystal cave, and on a smaller scale.

The Cave of Swords is a tantalizing clue

that there may be more caves to discover with

entirely different formations that defy comparison.

And that's exactly what a team

of climbers seek to find out a

kilometer away on the surface.

Naica project climber and rescuer

Marc Beverly now prepares to see

what marvels may await him on

a daring descent into the unknown.

It's a perfectly straight ventilation

shaft called a robin hole that drops

600 meters to the bottom of a mine.

A cave has been detected at 150 meters.

A drop equivalent to climbing down a 50 story skyscraper.

I think that's good.

Swivel just a tad 'cause I gotta

move this leg off the steel.

A tripod feeds all the

ropes to the bottom for climbers and gear.

Is climbing down worth the risk?

Another team is here to help find out.

They're engineers conducting a survey

with a technique called geoelectric mapping.

Step one is laying electrodes in

the ground around the robin hole.

- So geoelectric mapping, you're using

an electric current to create a three dimensional

map of the structure that's beneath us?

- What we do is we pound input of

direct current into the subsurface.

Through these electrodes that they

drop into the ground and they

are separated given to measurement.

Okay, so he calculates according

to the type of rock and how deep he

wants to go into the survey, he calculates

the distance between the electrodes.

Cables are strung between the electrodes.

An electric current is charged through the cable.

The result will be a three dimensional

image of the underground area.

If there is a cave here, the map should show it.

It will take a day to get results.

In the meantime, Marc Beverly will

take the direct approach to drop down

a rope 50 stories alone, in pitch black,

with no chance of rescue if something goes wrong.

It's not gonna change, right?

- No, that's fine.

Loose rock, even small pebbles,

turn into lethal projectiles if they fall on his descent.

So that's an adjustable for you.

Once in the cave, there's no way

no way of knowing whether the floor will

collapse or if the air is poisonous.

No human has ever been there.

It's a straight down descent into the unknown.

A custom made single rope can hold up

to two and a half tons of climbers and gear.

You can just take that whole

carabiner out, think you can do it.

The linchpin is a winch

attached to Beverly's truck.

Built for loggers to move trees,

climbers will be raised and lowered

by this small, powerful winch.

- We got good communications with our crew down below.

I'm feeding the rope, but I have a

hands free device right here which

is, if something happened to me,

if I just pass out, I'm obviously

lowering him with one hand, but if I

let go, then this would catch them.

We got a special carabiner that's made

so that if it gets cross loaded

it's not gonna break in any situation.

If you can imagine putting 27 of

me on this one rope, that's about

what this rope would hold as a

minimum breaking strength, so that's

a pretty good, strong rope right here.

The time has come for a first attempt.

Beverly will wear a high definition helmet

camera to provide real time images to the surface.

- All right, great.

- We still have minicam on top of it

so we can see whatever's going on with you.

Marc, put the helmet on,

don't worry about the rest of that.

Time to go.

- All right.

Fully weight this system, lower out.

A custom made single rope

can hold up to two and a half tons.

- Good test, let's see how it goes.

But if it fails,

it's a 600 meter drop to certain death.

It will take 10 minutes for Beverly

to drop to 150 meters, the level

where an unexplored caved awaits.

His descent is monitored from the surface.

60 meters.

60 meters.

The camera's working pretty good.

By dropping straight down the

middle of the hole, Beverly hopes to

avoid cutting the rope on sharp edges,

an accident that he would not survive.

Woo hoo hoo hoo hoo!

Big drop, big hole!

100.

110.

Beverly is now approaching his target.

Here comes another marker, 110.

No, no!

At the moment of discovery,

the signal to the surface is lost.

- Hey Marc, Justin.

Radio check.

Roger that.

All right, what do we got here?

We got a bit of a, we got a bit of a jog.

Looks like cave possibility maybe.

Hey guys.

Go ahead, Marc.

I got something.

- All right, let us know, sir.

, it's a cave.

Beverly is met with a

blast of heat that immediately fogs the lens.

It's a steam bath if

you go one foot outside of the hole.

The robin hole is an

air shaft designed to cool the mine.

No one had anticipated the cave would be so hot.

He clears the lens and keeps it from

fogging by staying in the cool tunnel.

It's amazing.

I poke my head marginally outside of this hole

and into the cave and it's extremely hot.

What's your definition of hot?

Like wow, it's warm.

Copy that.

So check this out, so as soon

as I grabbed the first stone, it felt

like it was radioactive, it was so hot.

I don't know how far this pocket goes,

it looks like it's about a 20 degree

angle off axis from horizontal.

I'm gonna continue on down.

Beverly detaches from the rope.

From here on in, he's on his own.

See that pull up on your light?

There's no way of knowing what he is seeing.

No way of knowing whether he is trapped or even killed.

Oh come on, come on.

Finally, a signal from below.

Up we go.

All right.

Look at that, that's sweet.

And the long wait as

the winch pulls Marc the length of

a city skyscraper to the surface.

An anxious team waits to find out what he's seen.

10 meters!

Woo hoo hoo hoo!

.

- Hey man.

Yeah buddy, that's freakin' awesome.

Three feet, two feet, one foot, stop, all stop.

- Woohoo!

That's what I'm talking about!

Exactly.

Right here.

Wow.

- How you doing, buddy?

- Awesome.

There's a small cave in there, yeah.

It's about, I don't know, a meter and

a half high and then it just goes

back and you can't see the end.

- There were actually crystals with the facets

that you could see, even tiny ones, or...

- There's some tiny ones in there,

they're small, you can see them up

on the ceiling like maybe they were

forming, but nothing like Crystalis or Espadas.

- Like the big big ones then.

- No, I didn't see them, but that

doesn't mean they couldn't be around the

corner maybe, I don't know, it's hard to say.

The team knows that they

have just scratched the surface.

Tomorrow they will go back to determine if this

unexplored cavern leads to another crystal cave.

They will risk their lives to find out.

This passage just curves

around to the left here I think.

There is another stunning

cavern near the crystal cave.

A cave that the miners say may have a

passageway to an undiscovered world of crystal marvels.

Here's a fracture here.

Oh yeah, I see that.

A water course.

Ooh, look at that, look at that.

It's a gypsum flower.

Nice.

Very pretty.

Look, it's slightly pink from the iron.

From the iron yes, look

at all the iron on the ceiling.

We need to sample that.

We need to sample the iron around

it, I don't wanna touch that beautiful--

The water course goes all the way down.

Scientists Penny Boston

and Mike Spildee check it out.

- I think the cave is up here

right around the corner to the left.

It's called The Queen's Eye.

It's about a 150 meter walk down the

tunnel from the entrance to the crystal cave.

Very different in scale from the other cave.

There it is, I see it.

The Queen's Eye has

a gem-like crystal at its center.

The eye.

If it were not for the overwhelming

crystal cave out the corridor,

this cave alone would be considered

one of the world's great marvels.

It's about 35 degrees celsius in here.

Not as punishing, but still very humid.

Ouch.

Yeah, they're sharp aren't they?

Look at that, it's like being

on the inside of a cut gem, isn't it?

It's just flowerless.

And the climb to the

top of The Queen's Eye is much more

treacherous than anything in the crystal cave.

That's just where Boston and Spildee want to go.

I'm gonna climb down through here.

There's a pool of water

that may contain bacteria and

viruses for further study.

The last time that we were

here there was not the abundance of water

that there is this time, and this is a difference

that we think is made very significant.

This allows minerals and various

other compounds to dissolve in the water,

but it also means that bacteria that

are living in the rock fracture habitat

also let go and go weee and jump into

the water flow, and so this allows

us to get access to organisms that

we weren't able to see before.

There is also biological

growth on the crystals here that

cannot be found in the crystal cave.

You got it?

Yeah, perfect.

Oh yeah, very nice.

As they get samples,

caver Mario Corsolini peers into the

tiny passageways near the cave's entrance.

The Queen's Eye is so close to the

crystal cave, and in a direct line

to the mysterious crevasse.

It's a tantalizing possibility that this

is the secret back door to the crystal cave.

But Corsolini encounters tunnels

that are too small for a man to pass.

A detailed scouring of the cave reveals no passageways.

Only astounding beauty.

And there is another cave nearby

that has its own unique shapes.

The explorers call it The Cave of Sails.

This chamber, about the size of

a football field, has the same

deadly heat as the crystal cave.

And it has a feature that the crystal cave does not.

The crystals here are regrowing.

Scientists believe the cave was

emptied of water 20 years ago and

these delicate precious crystals

grew upward, undisturbed by human explorers.

It's a tantalizing clue of what

would happen in the crystal cave

if it were to be left to nature.

The crystals would, in effect, reawaken.

Now the Naica project scientists

in the crystal cave begin the search

for viruses in this deadly, hot environment.

,

make us dress up like we're going

on a polar expedition, but it's

the hottest place I've ever been to.

Danielle Winget is a

biologist seeking to find answers

in the hellish conditions at Naica.

It's an almost entirely

microbial ecosystem, so there are no

big organisms here, there are no insects,

there's no animals, it's all bacteria.

Viruses are one of the primary

predators of bacteria and so we

anticipate finding them here.

The biologists believe

the viruses will be found in water.

There's water everywhere in this mine complex.

Huge pipes and pumps redirect 50 degree

celsius scalding water out of the mine.

They go to a place the miners call Hell.

It's at the mine's deepest point,

more than 500 meters down.

- We're gonna collect some small water

samples first from the pipe, then from

the wall back there, up on the floor

of this pool, and also some plaque

stuffed by the back wall.

- Okay, so be careful.

- She doesn't want me to wash away!

They have chosen not

to wear the bulky protective suits,

sacrificing a longer mission time for speed.

This gives them less than five minutes to work.

After that, their bodies can no longer cope with the heat.

Toxins attack the brain, organs fail.

- Got it?

- Yeah, yup. - Good.

- Looks like the water hit right at 49.

- Okay, 49.

- And the nearest about 42.

The race is on to

collect water and soil samples

for the scientific team to analyze.

Severe tremor sets in as Winget's body overheats.

- This is...

Water from one of the drips that

was coming off from right above

where I collected the wall sample.

Time is up.

They have to go.

But these explorers are pushed

to their physical limits.

It will take hours for their core

temperatures to return to normal.

A makeshift lab is set up on the surface.

Here the water is filtered down and viruses captured.

So what we're doing is

we're capturing all the bacteria

on this fine filter which is yellow.

That has a 200 nanometer core size, so very small.

We'll trap all the bacteria in that,

but the viruses should go through.

By taking the bacteria out, then we can

extract that material and then we

can get, we'll be sequencing the DNA

from those bacteria and trying to figure

out whether it's complicated or pretty simple.

When the results come

in, the team hits the jackpot.

- So we are just full of viruses.

Excellent.

- Let me see, let me see, let me see.

- Excellent, take a look.

There are as many as 10 million

viruses in a single milliliter of this water.

Far more than the team expected

to find in such a hostile environment.

So we'll definitely

be able to get DNA out of those babies.

Yes!

- Yay!

These samples will be

taken back to the lab for full DNA sequencing.

Back in the crystal cave, Mario Corsolini

continues to explore the treacherous

cavern that lies beyond the deadly crevasse.

Take your time, nice and slow, watch your feet.

He's looking for an access way

that may lead to another crystal cave.

But the camera arm proves too

cumbersome to handle in the punishing heat.

After two days of adjustments,

the ice cube that was meant to bring

the explorers relief is still not working.

The crystal cave is unforgiving on technology.

The air conditioning system that

worked in test after test fails.

This is the latest in a long line of

devices for the Naica project team, seeking

technological ways to combat the deadly heat.

Sensors attached to the explorers were devised

to monitor heart and blood pressure rates to

provide an early warning system

against extreme heat exposure.

But only low tech works in the cave.

Even then, no technology can be trusted.

Explorers have to be aware of the

messages coming from their bodies

and act fast before it's too late.

Scientists continue on various missions,

working at a constant pace.

They know that the crystal cave

will soon be flooded and this is

their last chance to unlock its mysteries.

- Okay.

These water samples may give

us some keys to looking at the way

most of the Earth was in the past,

now these are extreme environments,

but you can imagine if you went back in time

most of the Earth was very hot and very wet

and these are the kind of conditions

that you would expect life to have

been created and it's also the kinds

of conditions that perhaps might

be representative of lifeforms

that we might find in other planets

and again, so perhaps Naica will give us a

window into our search for life on other worlds.

- Good!

Fabulous.

Meanwhile, at the robin hole,

Marc Beverly prepares for a second descent.

This time with the film crew in an effort

to return with images from down below.

- I'm really anxious to go down

to the very bottom of this and see...

He reviews the footage

from the first descent with the scientific team.

- It's hard to tell because, again,

you're moving around a lot really

quickly, so maybe we could get

some more stills next time.

- Yeah, it's pretty hard not to

move around when you're so excited.

Could you tell if

there were crystals down there?

- Yeah, there's definitely crystals,

there's small crystals and they're

completely all over the place, on the ceiling.

- Just on the ceiling?

- Seemed like just on the ceiling,

but there's a lot of powder on the floor,

so I mean we could brush away

and see what's underneath. - Right.

- Maybe we can plan if there's

a way of going farther, we probably

need to do more planning.

- Sure.

- It sure is hot down there, you know?

- Yeah, it's entertaining.

Beverly's not crazy about

the idea of taking three extra people

down to a potentially dangerous cave.

All right, we're good.

I think we're ready for a lower.

Even for his experienced

climbers it is a tremendous risk.

Everything depends upon his planning.

A single mistake spells certain death,

plummeting 600 meters straight down.

Tensions are running high as

cameras and crew make their descent.

This time the objective is to

get deep into the cave and see

if it leads to another crystal cavern.

A black, unknown cavern awaits below.

As the surface world disappears.

Yeah, this hole is amazing.

150 meters.

10 minutes.

A winch built for dragging giant trees now holds

the lives of five men on a single one inch rope.

There you go.

This is it.

We're in Naica, Naica Mountain.

Justin's entering the cave right now.

Angie, this is Justin.

Go ahead and lower approximately five feet, five feet.

- Copy.

- All right Manuel, I'm gonna give

you a belay off of this and pull you in.

All right Manuel, we're gonna need you

to stop filming for a moment and crawl on in.

- Wow.

Holy smokes, huh?

Check this out.

We got a fairly significant wind right here.

It's actually going up this tube, it's 1,500 feet

all the way from the top to the bottom,

we're about 450 feet down right now

and you can see the condensation

dripping from the interface of

the two temperatures of the air.

We're gonna go explore this thing, come on, let's go.

Clipping in here?

Yeah, I just, I got all this on there.

- All right great, holy smokes.

Watch my glasses.

Watch this, ready?

That's crazy, huh?

The explorers fear

that the impact of the drill which

discovered this cave could have

created giant deadly cracks

dropping off into the abyss.

The temperature is 45 degrees celsius.

It would kill them in half an hour

if not for the nearby relief of

cool air at The robin hole.

Wow.

- Oh yeah.

If the crystal cave

is Heaven, this place is Hell.

A blast of hot air that far exceeds

the giant crystal cave pulses

from some unseen cavern at the back.

No human could last here more than

a few minutes if it were not for

the cool air from the nearby shaft.

- Robin hole.

.

Strange formations unlike

any ever seen grow on walls and floors.

No sign of giant crystals, but everywhere

there are other marvels unlike

anything ever discovered on Earth.

Dude, this is virgin,

this is pristine, this is as good

as it's ever gonna get for us.

Nothing more.

Tiny filament crystals

that look like fiber optics, but these

are made by nature, not man.

A single breath could destroy them forever.

The edges of the cave are covered

in cauliflower shapes often seen in

other caves, but not on this scale.

They resemble coral, an unlikely sight in a desert cavern.

- There's lots of little broccoflower crystals

everywhere, not just on top, but also on the bottom.

This is as far as we go down.

There's also some very fine crystals

that appear to be selenite crystals,

so it looks like if you could get

down further without disrupting any of

the crystals, which obviously we can't,

but if I could pinch this off

and it might go down there which

means, in caving terminology, if something

"goes" that means the passage continues.

Some of the finer

crystals grow in bundles and clumps looking

more like creatures than mineral formations.

They determine that this cave

is about 50 by 50 meters with

a three meter ceiling that drops

in some places to less than a meter.

There is one narrow tunnel leading

off it that may lead to another cave.

It's a whole new world, not like any world we know.

These are delicate features, look at this.

Look at that.

Despite its incredible heat,

and because of its unique white shapes,

the team decides to call it the ice palace.

Been a lot more of those hairline

crystals forming right here on this edge.

Right where all this cloud begins.

The team seeks a passage

at the rear of the cave to see if

it leads to another crystal cavern

and is met with a blast of hot air.

Wow!

I've got active air blowing across

my face at probably 10 miles an hour.

Dude, this is absolutely awesome.

It's insane, if I move my

head up like this I can feel air move

out of that hole and hit me in the face.

Yeah, it's running right

along the top of the cave.

This is how this cave is heated.

Drop your head, you don't feel it.

Right, so I cannot feel it

right now, and then I feel active here.

It's coming out of this hole.

They wonder if this

is the path to a crystal cave.

It keeps going.

Oh no way.

Yeah.

Don't kill yourself, dude.

A path filled with

countless magnificent chambers.

Marc, just be careful, dude.

But each one deadlier than

the last, further from escape to cooler air.

From this point on, Beverly documents

what he sees with a personal video recorder.

Absolutely crazy.

We're in a really tight crawlspace and this thing goes.

And the ground is hot.

It's very warm.

The heat blasts in at 15 kilometers

per hour from some unseen source beyond.

This is absolutely amazing.

What I've never seen is one of these things right here.

Oh I see what you see.

It's a cotton ball, selenite cotton ball,

in-between aragonite broccoflower essentially.

Amazing.

.

I'll take a peek this way.

Oh Marc, this is crazy.

This is gorgeous.

It's hot without to turn around.

Okay.

I'm burnt, very burnt.

The tunnel drops to another cave.

Exploring it is impossible.

It is too hot, too cramped.

Too dangerous.

We're outta here.

Let's go.

If there is another crystal cave,

they would die trying to find it this way.

Their work continues, collecting more

samples for the scientists to analyze.

These are all crystals, you can see

there's some dirt that's been stuck

on them, but they're very very opaque.

Crystals in the running along the fault line.

Time is up.

The crew now returns to the world at the surface.

But Marc Beverly decides to make

one daring push alone to descent to

the bottom of the shaft to see if

there is any evidence of other caves.

You be safe, take your time.

600 meters on a single rope

with no one to save him if something goes wrong.

Hours pass with no communications.

The surface team is tired, frustrated, even scared.

A horn signal.

Haul begins.

But something is wrong.

Marc Beverly is not on the rope.

- Lower!

Lower?

Yeah.

I think he meant for us to lower it.

I think he disconnected at the

bottom and meant for us to lower

it more so he could reconnect.

Finally the horn sounds again.

A half hour long ascent reveals a

Beverly who is soaking and freezing

cold in the near zero desert air.

- Give them a signal.

- Slow, slow!

Slow!

- Hey, what's up, baby?

You don't need to pass that knot.

He returns from the bottom of a

shaft that is deeper than the CN Tower is tall.

Wow, it's so much warmer

up here, it's not even funny.

I can just get out probably.

If I could actually physically move.

I'm so, so frozen.

- I got a hot tea and stuff for you in the tent.

and go to the tent.

Yeah, just go over there.

I think they wanna talk to you for a second.

Let me get you a jacket.

This is real soaking wet.

So there's lots of...

Lots of pit and some cave.

There's a small little area which

is, it's really fascinating.

Beverly is wet because the

shaft was overflowing with scorching water,

streaming like a waterfall and

dropping into the mine down below.

Extra coat, gloves.

- Thanks.

At about 4110, there was just

water pouring pouring pouring,

then it gets down to the bottom,

but there's just some really big crystals,

I think, I hope I got some images of it.

Beverly does not know

that his helmet camera failed

somewhere in the depths of the robin hole,

probably at the waterfall.

- You're just in this convection...

Cylinder of air and, thanks, and...

Get some freezing windchill effect.

- Oh it's so cold!

But regardless of the

camera's failure, he has visually

confirmed that there are no more

caves to be discovered in the shaft.

- That's about the only crystal,

there was a few more I can't quite

remember 'cause it's all a little foggy now.

As Beverly talks to the

crew on the surface, it's clear

that hypothermia is setting in.

- Okay.

I'm pretty cold.

His team gets him to

the tent for dry clothes and heat.

When Beverly recuperates, they will

continue their push of the cave down below.

To see what other mysteries it might reveal.

.

- Yeah, and the same kinds of plants,

.

After days of deadly work in the

crystal cave, the scientific team checks in with

the climbers of the nearby robin hole.

The Naica project's work continues as Marc Beverly

collects more samples for the team to analyze.

The scientists determine that the

cauliflower shapes are aragonite,

a mineral commonly found in marine environments.

The spaghetti-like ones are also aragonite.

- There you go.

While the filaments

resembling fiber optics are selenite.

Baby versions of the giants in the crystal cave.

- 16 meters.

Beverly draws a detailed

map of the cave to ensure that his findings

can be documented for future reference.

Climber Jason Williams describes

what they are seeing 150 meters down below.

- The cave down there, and once you

go into it, it actually opens up into,

it's an entire room, but the ceiling isn't

very high, it's probably only about

four or five feet high at the tallest.

If you go back a little ways, there's a

little upper room where it just gains

probably four feet, but if you go in

that four feet, the temperature

gets really really hot back there.

What the interesting thing to

you guys might be, is that the

bottom of the cave is very solid.

Crystals, minerals, and rock.

If you hit your head on the ceiling

in the bottom of the cave, clunk clunk.

If you're hit your head on the

ceiling in the top of the cave,

it just covers you in mud.

- Gush gush.

- Gush gush. - Oh, okay.

- We like gush.

- Yeah.

- So and the other thing is--

- So it's moist then?

- It's moist throughout the whole upper part of the cave.

- And we can just stick one of our

tubes straight up into the roof of

the cave and you guys pull back out,

it'll give us a cord, then we could layer

it and see what was in the different layers.

Hopefully the stuff at the surface

would be one community and the stuff up

at the top would be the older stuff.

- We want both.

Yeah, we want both and

we're gonna look for viruses and bacteria.

- Yeah.

- And anything else.

And anything else.

And there is good news.

The team of geoelectric mappers have hit pay dirt.

- Okay, let's go 50 more.

Oh wow, look at that.

In 90 minutes.

90 meters, and this

is one, two, three, four.

Well where is the robin in relation to this?

That's only 90 meters down, where that break occurred

in the robin, that was much deeper, that was about 130.

That was further inside,

let's go to another slice further.

Yeah, maybe 130?

Yeah, look at that.

Yeah, you still see really high resistivity.

Conceivably, if there is an opening

here, if that trend carries through,

we could make it up to a much bigger cave.

- Si, si.

So in the end we're gonna

put all this together and we'll get

a 3D map of the entire area so we can see

an outline of where that chamber would sit.

Very cool, that's awesome, so we'll be

able to take the actual, the notes from

down there and map it out to this

3D map that we get here and get a

real picture of what's going on.

The geoelectric plan

indicates that the ice palace cave

may be linked to other caverns.

But whether humans can venture

from cave to cave is a mystery

that only exploration can solve.

The scientists report that in

the crystal cave they have penetrated

the long back corridor, but have not

been able to prove that it leads

to another crystal cavern.

The scientists ask Marc Beverly

to bring his team down to see if

their climbing expertise can be

of help in the deadly tunnel that

they think leads to another cave.

Together they will try to unlock

the cave's final secrets.

- What I'll do is I'll have the box,

I'll be able to look and I'll say move right.

Beverly will use the

remote camera to probe the tiny

access ways that lead off the tunnel.

- Our team tactic is to move really

light and fast, so we're taking one

bag, it's gonna have a camera on the

top of it, we're gonna have a liter

and a half of fluid with two frozen

electrolyte packets with us.

Maybe an ice pack or two in there

to keep all that cool so we can

recuperate as we go through and

that's gonna be our gear.

Beverly is more philosophical

about the risk they are about to take.

- We see this hole down there and it's

like the little, this little thing in

the back of your mind saying go check it out.

Go check it out and see what's

back there, see what you can find.

People think that's crazy, they're like

why would you do that, why would you

expose yourself to this and really it

comes down to living life and this

is all about the human experience,

about living and not just doing

the same thing and getting lost

in the monotony of the day.

The climbers decide that they will

wear ice vests, but no protective suits.

They believe the suits will only slow them down.

They will sacrifice safety for speed.

- All right, well let's roll.

Time for a first push.

These explorers know that if someone slips and

is knocked out, there's no hope of rescue.

They reach the end of the tunnel.

Without respirators and suits,

it is a race against time.

The climbers have marked the area with

their gear, but now they are disoriented.

The crystals and boreholes look the same at every turn.

It's a 45 degree claustrophobic house of mirrors.

Where are you going, up there?

That's where I left the bag?

Yeah.

Just wanted to make sure.

If you go, I'll bring you back.

- Okay.

.

- Like we didn't even go to this the last time.

I went down there, I see it, that goes

to the mirrors, this way.

Yes, this way.

After 10 searing minutes,

they abandon the mission.

So there's several holes, some dead end,

and we wanna make sure we get it right.

They return to mission

control exhausted and defeated.

- Good job, man.

Beverly is daunted.

The theory of traveling fast and light didn't work.

- We are ready to go.

After a day's rest, a second attempt.

This time the explorers wear no ice

at all despite the lethal heat.

They beeline straight for the hole that they believe

is the best way to find another crystal cave.

Beverly is certain he can see a

passage at the bottom of the hole.

We got crystals straight in front of us.

We got lots of heat of course.

We're just trying to visually

document what we have as far as the

possibility for the passage that goes.

Okay, I got flat down the glow stick,

so we'll see what happens.

Going in again.

Keep going, I'm looking on the viewfinder, Marc.

Go down, but you still, it looks like

about one to two feet that you

need to extend it inside of the cave.

Sounds good.

- Okay, lock it down.

That's a good shot.

- Okay, I gotta tighten the stuff.

going upside down, okay.

again.

After five punishing

minutes, a tantalizing clue.

In the top right corner of the passageway, a void.

This looks to Beverly like a passage to another cave.

This access way is too small for human exploration.

Okay, good.

Anything else?

That's it.

I think that's it guys, we're done.

That was intense.

.

Yeah, all right, everybody .

- Just take your time, watch your groin,

watch your ribs, you could easily

break a rib on one of these things.

But Beverly feels

within reach of solving the mystery,

that there is another crystal cave.

He reviews his footage with

Victor Torres in mission control.

- But it's high, okay stop there.

On The right hand corner you can

see that there's some steam up in that

area which to me is like that's a void.

- Give an idea of how wide is that void there.

- It's only 25 centimeters by 25 centimeters.

Not enough to--

Yeah, you know, not enough to crawl through.

It's a possibility.

It's indeterminant, let's call it that.

It's not positive, it's not negative, indeterminant.

Indeterminant means even if

there are other caverns connected by

air shafts, no human explorer can go further.

But it was worth the risk to explore beyond the crevasse.

New, wondrous crystals are discovered in this

passageway not seen or filmed on previous missions.

A sword-like one that the team dubs Excalibur.

It would be a centerpiece in any museum.

Here, it is just a curiosity.

Another crystal on the floor that

is like a perfectly cut gem.

And all around, walls and pillars

of pristine crystals that rival

those in the large cavern down below.

The explorers have concluded for now

that the crystal cave and the ice

palace are not physically connected,

but they are both part of a much larger system of caves.

It includes The Cave of Swords,

The Cave of Sails, and The Queen's Eye.

These caves have revealed new life.

I hate to leave this

environment because I think that

we probably will never see it again.

This is an extraordinary opportunity to

get a brief window in time that we

can look into a part of the subsurface

that we don't normally see, so leaving it,

I'm excited about what we have sampled

and what I think that we will find,

I think it will be very significant,

but I'm also very nostalgic about

the fact that I've seen amazing

beauties during these expeditions

and I won't see those again.

It's a bittersweet moment.

Millions of viruses have

been discovered in the crystal cave's water.

The scientists determine that the

life here is the same as at the

hydrothermal vents at the bottom of the sea.

Bacteria and viruses coexisting in

one of the toughest environments on Earth.

Their ongoing studies are blazing a trail for

an understanding of life on other planets.

The mission is done.

Now everyone returns to the original

crystal cave for one last visit to say

goodbye as it may soon be gone forever.

Even if the ice palace cave does lead

to a series of other caves, it too is

no longer an option for future explorers.

The mine has decided to cover the robin hole.

No one will ever explore the ice palace again.

This may be the last time anyone

will see these natural wonders.

- I love this place.

But that's not necessarily a bad thing.

Soon the crystal cave may return

to its natural state underwater.

The crystals may continue to grow,

perhaps to be rediscovered at another time.

Sometimes the best things on Earth

are the things we leave alone.