Original subtitles

BILL I received a phone call in January of 1988.

And they said, uh, there's an amazing new discovery

in the Sierra Juarez mountains of Eastern Oaxaca, Mexico.

BILL By the end of that brief re-con,

we realized that, that we were on to something.

The scale of which is totally unprecedented.

There's a massive entrance at the top of the mountain

and an exit at the bottom where the river flows out

over 9,000 feet vertically below.

That makes Chevé the deepest cave on Earth, in theory.

Whether a human can go through or not,

that's what we're here to, uh, determine.

Oh God.

Okay.

BILL This is not really a, uh, a race course.

This is a fluency test to make sure you know

what the heck you're doing before you go in the cave.

Everything you see here. Every one of these complicated little maneuvers,

that exists in the cave. This is not a fabrication here.

Okay.

Uh-oh. Careful. Uh-oh.

Think about where it's gonna go.

This course is here because a guy died in this cave.

Came in.

Had never trained for the type of rope work that was happening.

BILL And went down and he landed on his head.

Ever since then we instituted this,

what we call a rebelay course,

uh, to test everybody who comes here.

Most of these people are world class.

Some of them are newer, younger people.

That's good, switch to repel.

We have a nominal 40 minute time to do the whole course,

but, really, most people who are fluent will be under 20.

Descender's off. Our descender off.

That's off. One, two.

17 flat.

Whoa! Very good.

And that was textbook except for one or two.

Yeah.

PABLO My name is Pablo Durana and I am the cinematographer

going in the cave.

I've gone on expeditions in Greenland, in Antarctica.

Uh, so, environments that are, are difficult.

PABLO But I've never been in a cave as deep as this or as,

as technical or complicated.

You know, this is true exploration and,

you know, Chevé is at the top of this big mystery.

Hopefully they'll discover the passage that'll make this

the deepest cave in the world.

Uh, so, uh, just confirming,

we will be restarting the restock, uh, supply train

hopefully tomorrow, if not then the very next day, uh,

and people will be moving back into camp one and camp two for a shuttle, over.

The distance and the depth involved, uh, in,

in getting to the bottom of Chevé

is singular among the caves in the world.

So, it's massive effort that takes thousands of pounds of equipment and

months and months of planning to even get us here.

Camp one? Basecamp here, over.

You guys on the line? We need to talk to you.

BEV On the surface, you got a team of people

who are packing up all the food, all the supplies,

making sure that everything is getting into that multi-day supply chain,

so that it can arrive down into the cave.

Well, so purgatory borehole is aligned with sump one.

BILL Over the past 30 years,

we've established a chain of underground camps

leading deeper and deeper into the cave.

All the way to our current front line of exploration

about five kilometers from the entrance.

For those who have an idea to go to camp five,

I'm gonna tell you right now, the only people going to camp five

are those whose skill sets are specifically needed there.

Okay? It is not a pleasant place.

I think we have, uh, ten, uh, nations involved in this project this year.

So what unfolds is gonna be an orchestrated team of

highly trained individuals and getting a little bit of luck.

This is the last terrestrial frontier and it is the real deal.

We've laid siege to this mountain.

We've got 60 people.

We've got the best technology and some of the world's best cavers.

And our goal is to make this cave the deepest cave in the world.

Think we could get by with one roll of flagging tape?

Yes. I might have to.

All right, survey kit.

Right on top and that is it.

Little on the heavy side.

40.

BILL Right now I'm headed down to the front line to camp five

to rally the lead team for a big push deeper into the cave.

It's like we're going into battle.

We are! -

Everybody ready to roll? Let's go.

BILL From the entrance it's five hours of travel

to reach the first supply camp.

This is an entrance you could fly, like, an airplane in to.

Uh, so, the first impression you get is that it's big

and it keeps giving you that impression all the way down.

BILL The entrance chamber itself goes for several hundred meters

before you can drop down through the floor

to the first rope pitch.

And when you hit the bottom you can now begin to hear

the Chevé River for the first time.

MAN Yeah, it'll definitely be of use deeper.

Okay, we'll put that in the out pile and then

somebody coming in next time, put that on their list for camp two.

BILL Camp one, it's there as an acclimatization camp

for people who are just showing up on the mountain.

You get acclimated to the, the altitude,

you get acclimated to just the physical brutality of,

of hauling heavy loads up and down.

I'm gonna say three liters of breakfast.

Uh, yeah, this is camp one.

Uh, we currently have, uh, four souls, uh, down here

with about 60 kilos of food, headed for camp two.

BILL Completing the journey down to camp two requires

a highly technical descent of a 500 foot underground waterfall.

Do you want me to wait for you down there?

Any moment feels okay for you to wait would be great,

...but I don't want you to get cold.

You're gonna have to step across,

go up about two meters and there's a traverse line.

Just clip it with your two cow's tails, don't screw around with a jumar.

Okay. Don't dally in there.

And don't do anything reckless either.

Rock!

BILL The worst thing that you can possibly have happen,

on an expedition, is to have someone die.

Okay? And I, I can tell you that from hard personal experience.

It's happened to me four times.

BILL When you look over the edge there,

you know that that's, you know, death staring you in the face.

And so you pay attention to everything you do.

This would not be a place to have a broken leg.

BILL Camps three and four were the furthest

we've been able to go for about 20 years,

until we found a bypass to a new route in 2017.

Now, camp five is our current front line of exploration.

Four full days of travel from the surface.

A collapsed tunnel has halted all forward progress from here.

We gotta, we gotta think out of the box here and,

and you know, finding a way on is number one,

- and survey is the next thing. Why waste time?

Also, make sure it's Bill-sized please.

That's gonna be a little hard to promise.

- Yeah.

I think a non-Bill-sized route forward is better than no route forward.

Well, I agree with that but...

But, it can be made Bill-sized, later.

It can be engineered. Yeah.

BILL Sean Lewis and Witek Hoffman are our specialists

on the front lines right now.

The idea is kind of like in playing any, any game.

You want to have your, your superstars out front and

everybody else is supporting them.

Okay. Got one.

I got interested in Chevé when I first came here in 2018.

SEAN I work very closely with Bill.

We've been working almost full-time.

Coordinating logistics.

Organizing the data and I think all the people on this expedition

are here because we share his dream.

BILL If the lead team can find a way through the collapsed tunnel,

we believe it will connect into a new passage

that leads all the way to the bottom.

Let's do a mental check to make sure I have everything ready,

I got a hammer drill, I got a bit...

Distorted sense of hope.

I got a distorted sense of hope.

BILL Sean is an interesting character.

He was a grad student working in physics.

It's a kinda thing where,

he just used it as a mathematical puzzle.

SEAN You know, there's clues every step of the way.

You can follow the wind, you can follow the water.

But truly, you know, the cave environment is it's own animal.

Rock.

Whew! Hello.

So we are, now try with some smoke

and see where the smoke actually going.

WITEK The stronger the smoke,

hopefully the bigger the spots between the rock are.

That stream, definitely wants to head up.

SEAN Some of the wind seemed to be going up,

which is a sign, very clear,

that there's an easier way to travel, for the air, up higher.

Here you can see it moving this way.

Oh yeah. Wow, it's strong here.

SEAN The wind can go places that we can't.

So, the question is, can we follow the wind?

That's coming up. And this is where we're gonna go.

Lots of loose rocks, so stay, stay back a little bit.

Mm-hmm.

Virgin territory is always filled with loose rocks.

Can you just grab my helmet, I don't wanna lose it.

Yeah.

Awesome.

I have no clue where, where I am.

I, I don't get how you do this. I really don't.

SEAN A lot of the people here

are very accustomed to being underground

in situations that would cause a lot of other people to...

feel claustrophobia or panic.

I wanna say it's scary but I never get scared.

This is starting to look really good again.

I can see a larger space above us so we're still, we're still

in the right track, we have to go up through the boulders

to find a big space above.

SEAN That puzzle aspect of caving,

to me, that's my happy place.

I'll never be happier than when I am pushing into something unknown.

Ah! Too tight.

That doesn't go, that doesn't go, this doesn't go.

Also I don't, it to make many moves and forget about how we got here.

That does happen, and it's very scary.

I would not want that to happen.

Ah, wow.

How the hell did you fit through that?

The big hope is that they'll break into a big, big tunnel with no boulders

and if that happens we could have multiple kilometers

of giant tunnels going down the mountain, no problem at all.

You know there's something above us, it's just driving me crazy.

We've checked five different holes at this point.

None of them have gone in to it but there's,

every-time I check there's a small space

and I can see something bigger above,

there's one more hole to check.

So they're in a spot where they can hear an echo,

which is really promising that there's a big chamber.

I'm so impressed with their determination.

They just don't stop.

What do you see right now?

There's a big of room just ahead.

Whoa!

Big room.

Borehole!

Oh my gosh, oh. Welcome!

That's all I gotta say.

This is huge. It's a nice feeling, huh?

Boom.

I think it might be one of the most beautiful rooms

in the whole cave actually.

Now, we go up.

SEAN Being the first person to set foot in a brand new place,

that no one's ever been before, uh...

It's really quite something.

SEAN Especially when you know that

there's a whole expedition behind you and

everyone's hoping that there's gonna be a big discovery.

We are on-line waiting for whatever you're gonna tell us.

SEAN We got it, Bill, this is...

Borehole, over.

Ah, go ahead and, uh, elaborate on that please?

We popped near the top of the slope in a borehole that was probably...

SEAN 15 meters high and...

About the same width.

Nicely done, guys.

BILL A new card on the table.

BILL This is the breakthrough

we've been waiting for.

We're now at a point where we are beyond this, uh,

large breakdown zone that had stopped exploration for 30 years.

So unusual and so beautiful.

BILL Camp 5.5

will be our new beach head for exploring

deeper into the cave than anybody has ever been.

Big enough for two people lying down.

Everything around here is just like, sharp, jagged boulders.

It's not meant for human habitation. We had to build everything.

So, building this bed...

Make it all nice and flat.

Protecting ourselves from the drips.

It's really important that we make the best use of every single day at this camp

because the expedition does have limited time

and limited resources and we want to make sure that

the frontier is being explored every day.

Wow, the republic of 5.5.

Things don't dry out much do they here?

No it's...

Mm, smells just terribly.

It's all wet and I can already feel it and smell it.

You know, I don't have any clean clothes,

I've been wearing the same socks to bed for three weeks.

I've got like three pairs of dirty shirts and that's it.

Right, and so it's like...

You know, after a while you just have to stop caring about that stuff but.

♪ Down, down, down you go ♪

♪ Down the hole, down you go ♪

♪ Jack you never see the skies and your working in a dungeon ♪

Being out, days from the surface,

is a, is a really, uh, wild feeling.

You know, that there's 5,000, 6,000 feet of rock straight above you.

Definitely think about that a lot.

I've been here, uh, six weeks.

It's actually my longest stay on an expedition. Um, ever.

COREY And, and I admit too, you know, I get a bit homesick, uh,

when I'm, when I'm gone this long.

There is so little that's familiar down there, you know,

compared to the surface.

Everything around you is kinda, just kinda alien.

In your normal life, when you turn off the lights,

eventually there's a little light coming from somewhere else

and your eyes adjust.

BEV When it's truly, completely dark,

your eyes never adjust. You can't see anything.

And, for me, that's a really kind of comfortable, cozy feeling.

To have left behind all the chaos and static of the surface

of our everyday, hectic lives,

and to be able to focus on one single task.

- Good night.

Safe to come up? Yeah.

The current world depth record is 7,257 feet

in a cave called Veryovkina in Eastern Europe.

If we make it to the bottom of Chevé,

we'll break that record by over 1,500 feet.

If this turns out to be the main route,

we'll have to de-rig the rope and push it over.

As the front of exploration get deeper and deeper

into the cave, there's a whole supply infrastructure

behind them consisting of a multiplying number of people

as you get farther and farther back toward the entrance.

Uh, so we've brought down, uh, something like

seven 55 liter sacks of gear

here and, uh, we've got about four sacks of climbing gear.

SEAN I know we're gonna need to resupply camp three and

just keep stuff moving forward and deeper into the cave.

PABLO I mean, this is what sets caving apart.

It's such a collective effort.

They're working like an army of ants and they're shuttling supplies in and out,

in and out for the people at the forefront to be able to push.

BILL It's harder to go deeper,

because every meter you go forward

puts you one more meter from the entrance.

And we're now at a point where

you might as well be on the far side of the moon.

MAN Three, two, one, zero. All engines running.

Lift off, we have a lift off. 32 minutes past the hour...

BILL When I was a kid, you know,

I wanted to be a, an astronaut.

MAN Okay, Neil we see you coming down the ladder now.

NEIL The view is beautiful, just beautiful.

BILL Watching Neil Armstrong and Buzz Aldrin land on the moon

That was, that was, that was something that just,

you know, burned it's way into my, my psyche.

MAN This is Houston reading you loud and clear, over.

BILL By the time I was in sixth grade,

I was interested in science and my Dad came home one Christmas

and got me one of these Gilbert chemistry sets.

And I was running experiments that were,

you know, graduate student level, organic chemistry, in my basement.

I was the classic nerd. I really never even got into dating until

I was almost at the end of college.

It was the goal of getting out and,

you know, getting into the astronaut corps.

And for nine years, I submitted applications.

You know, they had psychological tests,

they had physical tests.

I got a nice thin letter that said

I was too independent for the astronaut corps.

Which I cherish to this day.

BILL I went off to form my own company and ever since then

I have structured my life around exploration.

I'm 68.

I've sunk a lot of my life into this project here.

I wanna do the most exploration that I can during my lifetime.

And, uh, Chevé is the challenge in exploration right now, on Earth.

I think Bill's known that this is the deepest cave system

in the world for a long time and

coming back year after year after year and not getting there,

you get more and more attached.

Chevé will give you piece of spectacular tunnel

and then right when you think you've got it all, it'll stop.

If it was easy everyone would do it Bill.

You know, if it was easy it'd have been done 30 years ago.

Exactly, what would you be doing with your life now?

Hm, well I'm pretty happy where I am right here.

Mm-hmm, I know.

COREY I think it would be one of Bill's, you know,

great life accomplishments and, and the fulfillment of a dream

if he could see us, uh, break the world depth record.

And go to the bottom of the world.

BILL Right now, the entire expedition is focused

on the mission of those people out at Camp 5.5.

Those people, uh, who are pretty much

some of our best in terms of, uh, route finding.

What I do, do on the other side,

I know how to plan in advance, you know, food and logistics

and all the equipment here in base camp.

Oh I, I could cry right now.

It's so good to see ya.

All right, man no more harness.

BILL We have an A team of breakdown pushers out there

who, hopefully, in the next couple of days could be out beyond the world depth record

Here it is folks, you know, this is the wide open frontier.

It's unexplored, figure out how to do it.

BILL Camp 5.5 established our new front line

in an unexplored passage nine kilometers from the surface.

Now, the lead team needs to find a way out of that passage

that leads deeper into the cave.

I think we go this way?

Ho!

A big echo up there, somewhere.

I don't know if it's from the passage

that we just came out of because it's really tall and narrow.

BILL Corey is a proven, uh, super star when it comes to

finding a passage where you wouldn't expect it.

Sniffing out, you know, however, with sixth sense.

Uh, you know, where the cave goes and, and where the way into it is.

All of the wind, uh, that we expect to feel going

deeper into the cave is moving through this passage.

Wow, that's what we've been chasing for a week.

Well, 30 years, yeah. For pretty long, yeah.

COREY I first came to Sistema Chevé in 2013.

To me, uh, Chevé is heaven.

But there's times when what you have to do is hellish.

Some cave passages get so large, uh, that the ceilings collapse.

The passages can actually, eventually, totally fill themselves,

sometimes to the ceiling, with breakdown.

Oh God. Okay.

Ow.

Well.

I think the way on is that way.

COREY Going through breakdown is like, uh,

it's like a body puzzle and you're surrounded by rocks.

If you go in one hole, suddenly you're presented with five more.

Then if you go in any of those five,

you might have three to six options to keep going.

PABLO When you're climbing, you know if an accident happens,

there's usually a heli-rescue or something.

The rescue potential here is...

Nonexistent.

I think it was down here.

Cavers go back to breakdown areas over and over and over again

and don't get through and then one day after 20 pushes

into this breakdown pile there's a magic route that,

that gets you to the other side of the pile.

And then boom.

Oh, my goodness.

BILL The team at Camp 5.5 have reported that they had finally, uh,

gotten into solid rock tunnel.

We did it.

-

We're gonna start, uh, surveying it from here, uh.

From this point forward it's completely unexplored.

That experience of popping through into a space that's never been seen before.

It's like the closest you can get on Earth to, to going to a different planet.

It's something you know is new to human eyes.

Unbelievable.

What a day.

We surveyed approximately another kilometer and half.

Nice work!

We're past, uh, we climbed up 40 meters.

I told you it was steep.

And, boom! Almost 50.

Nice flat areas, hard packed clay,

not a lot of drips it looks like,

so this is a potential Camp six site.

Feels like this might actually be the best lead in any cave on Earth right now.

COREY Good morning Bill, this is Camp 5.5.

Uh, we have some interesting developments to share.

Uh, go ahead.

COREY We, uh, absolutely have...

A beautiful Camp six site.

Uh, it's currently, uh, about...

COREY Two hours from Camp 5.5.

BILL Nicely done guys.

Think about what you need, uh, from us to, uh, keep this going.

BILL We'll see you there in a year.

We've got the bull by the horns right now.

BILL Camp six is, uh, deeper than anybody has ever been

in Cueva Chevé.

It is the most remote bivouac anybody has ever put inside any cave on earth.

The hope is that it's a straight shot from here all the way to the bottom.

BILL I've been out for some time so

I'm ready to go in for the big push.

See you down there.

Bye. Bye, have fun.

BILL But it's five full days of travel

from the entrance for me to get down there and join them

and I wanna be there if this new tunnel is finally the one that goes.

See you on the bottom.

BILL While I'm working my way down

the lead team is out there

exploring deeper into the cave than humans have ever been.

Look at this bedrock.

Yeah. We got a, a lead up there.

For once the cave is branching out into a lot of directions.

Uh, it's a watershed moment in the history of Chevé potentially.

This is really cool.

Like, we could have really good going passage most of the way

and this is Colin, he's...

You ready to go? He's the real man.

You got it, we got... We go caving together.

How's it looking up there, my friend?

That's nice borehole.

I, I think we need to go investigate that.

I'm gonna look in this pocket over here.

Holy

The passage gets bigger!

Keeps going, huh?

Five kilometers of borehole, this is what it sounds like.

Not bad. Fast.

The chambers were finding now are insanely big.

100 foot high room right here.

And then this room that Adrian's going up into,

is double the height of that.

Light her up Adrian.

Wow.

Holy

- That's a giant mountain. Yes.

What do you think?

It's amazing, Chevé is unstoppable.

Unstoppable! -

The borehole is 60 meters tall, 50 meters wide.

I think this is likely one of the better days of caving

I will ever have in my entire life.

We broke the Chevé depth record.

We, yes, we made a cave deeper today.

Wo-oh!

♪ The way is wide and open ♪

SEAN You know, when you sing,

it's like there's a chorus in the cave.

So we named it Harmony Hall.

♪ The way is wide and open ♪

Another day in the dirt, huh?

Yeah, it was a good night's sleep, just a lot of pains that weren't there before.

Some point here, we keep going at this pace we’re all gonna

get up and just say, "My muscles don't work."

But, I guess until we run out of cocoa we can still get up, huh?

Yeah.

Come on Camp six, tell us you got something.

KATIE Camp six to Base camp.

Ah, here we go.

SEAN Hey Bill, so we made the cave deeper

and we mapped 2.1 kilometers yesterday, over.

Very nice. Uh, is it linear or is it, uh, labyrinthine?

SEAN Uh, sort of both.

SEAN We had been in this giant, giant room and

now all of a sudden it came to this little tunnel.

And at the bottom was a pool of water

and that was the end of the cave.

It was a sump. A place where the water fills up to the ceiling.

But there was hope.

There's a huge dome here with a possible passage coming in up there as well.

SEAN So there's a lead up there.

SEAN Up on the walls were tunnels.

The challenge was that these tunnels were really high up the wall.

Our plan was to just attack that, uh, climb with, with guns blazing...

COREY Because it does seem to be, uh, the best option.

BILL:How far total up the wall, vertical, uh, are you at your highest point?

It goes up about 40 vertical meters, over.

BILL That is a long way up.

It seems right now that we gotta go climbing.

We'll see ya on the flip side.

Nobody has been able to figure out a way onward.

The only thing that we can think of is that we have to try

an extremely tall overhung climb.

If we're gonna make this the world's deepest cave,

that's the way we have to go.

What do you think of Camp six, Bill?

Well, based on all the stories that I heard

somebody did some serious engineering.

Oh yes.

Yeah, it's, it's got some charm.

So is this thing right here, the, the climb?

Yeah, the top part of it.

I agree with Corey. The, of all the indicators are that that chamber is it.

It's where it's gotta go.

Yeah, days are ticking. We gotta get out there now.

I mean normally, you know, it's my position to kinda hang back

and let everybody, uh, do their thing, uh, but right now,

we're kinda down to the point where

if we lose a day, we lose the opportunity to get deeper.

SEAN What we're doing in here in Chevé

requires a massive siege effort. A huge expedition

and I've been sort of in a secondary leadership role in a lot of things.

For Bill to be underground someone has to be responsible

and be on the surface and he's asked me and Bev to take care of it so.

Yeah I have to go to the surface.

Which of course, I'm not happy about. But that's how it goes.

SEAN This is a team effort and I think everyone on the expedition

has that mentality even if some of us might have

different opinions about how things should be done.

The worst is having to leave a discovery when it's being explored and

the excitement is not just the first moment,

the excitement is the, um, experience of mapping as you go and,

you know, what's around the next bend.

No, this, this is definitely going.

SEAN Its really something to be a part of this project and,

and to be able to have the privilege of, of pushing that frontier.

BILL It's a six hour commute just to get to where the action is.

Don’t do anything that’s gonna bring a rock down on us.

Yeah, I'm gonna try really hard not to.

I hear anything move, I want you to get the heck out of there.

We're going into virgin territory.

You can step on a rock the size of a house and have it

roll over on you and I've actually had that happen.

BILL But I have an agenda and that is to prove that this is

officially the world's deepest cave

because it's out there to be had and you know what?

We're in a position where we can take it.

Let’s scout around.

We are, I would expect,

officially at the site of Camp seven.

BILL You could vaguely make out a whitish appearance on the roof,

white crystals that suggested that there was a tunnel up there

with air flow going through it.

We set Camp seven at that site so that we could wake up in

the morning and climb up the wall of that chamber.

Get into that tunnel and then keep going.

So we have one day of food.

We're short on all rigging supplies.

BILL Nobody has ever camped that far inside a cave before.

We have a gigantic logistics problem where it might take

seven to ten days or more to get the supplies that we need

down to the bottom of the cave and by that time it's too late.

And so, the weight of remoteness is on your mind when you're down there.

But, uh, you have to realize that these are precious opportunities.

We are privileged to be here right now quite frankly.

This is the furthest north anybody has been in this cave system and, uh,

with a little bit of luck we’ll find a way on right up there.

I reckon we'll climb up there.

BILL This climb is our last chance to find an exit

out of this room and deeper into the cave.

What we're looking for is a way how to get up into that hole,

60 or 70 meters up in the roof,

that looks like it's the main continuation of the cave.

All right, here we go.

Now that we're here, uh, we see that there are two waterfalls coming in

that, uh, might actually be a shorter route up the wall, less bolts.

Can't predict anything at this point.

We're just gonna try ‘em all and one of ‘em

might be the one that makes the connections.

All right-y.

How much rope is up there and how much do you need?

About 40 meters is up there. We got 40, plus 30.

We are running low on, uh, on resources.

GILLY Food, rigging bolts, rope.

How many you got there? Couple of extra carabiners.

Six. That's it, yeah?

Yep. We are...

Are we ready?

The entire team is counting on us,

so we're gonna burn whatever resources we have.

Bill's definitely, uh, built for this.

I mean he's, he has the optimism, he has the determination

to make stuff like this happen.

It takes a certain personality and Bill has a determination like no other.

BILL There has to be a way out of this room. It's too big.

There's too much air going into it,

that there has to be some sneak hole in the ceiling

that is the way on.

And so we gotta get up there and get the team an answer.

Woo-hoo!

You're out there beyond support.

So if you have a time sensitive injury,

say a compound fractured leg, forget it.

We're beyond a point where rescue is possible.

BILL I was scared to the point where I had to tell myself

to focus on what the hell I was doing because there was nothing but

crappy rock and mud all over everything.

Very few places to put bolts or anything else to hang on.

GILLY Meanwhile, I'm kind of looking at the lead

from the bottom and shining my light up and kinda getting a sense

for where we're going because it's so dark in this room,

that we can't even see where we're trying to climb to and that's

one of the huge challenges of doing a dome climb in a place like this.

You can't see where you're going.

We have not...

Five meters!

Five meters! Okay, thank you.

BILL We didn't have enough rope.

It was like half the length of what we really wanted.

And you're getting tired and your legs are getting constricted.

And the blood is not flowing through your legs

and you can only hang in a harness for so long in a free-fall position like that.

And it was like, looking up, I realized there was like,

six or eight bolt placements to go and Gilly's telling me

you got three meters of dynamic rope left.

BILL And there's no easy way to bail out from that

other than hanging on a single rock bolt 55 meters off the deck.

And trusting whether that crappy rock is gonna hold that bolt

while you try to get out of there.

So there was a lot of complicating thoughts going on

in my mind while I was doing it.

We reached it with just a very short bit of, of rope to spare.

- Okay! Whoa!

BILL Finally finished that last piece

to get the answer and, unfortunately, it went up and walled out.

Grab the rope.

Oh my God. So?

(bleep)!

Well this is it. We're out of bolts, we're out of rope,

and that down there is a drop we can't free-climb down.

BILL This is the end of the line.

We're out of supplies and out of options.

We spent the entire month of April

with some of the best cavers in the world,

by far, uh, down there and we struck out.

That climb was supposed to go.

Shot a lot of resources on that.

What I really wish I had is like,

through rock 3-D vision.

Just see that it's right over there.

BILL You never conquer anything down here.

If anything the cave conquers you

and so you go back and say, "All right,

- we couldn't get through this time. - What do we do to get through next time?"

We're out of here.

Was a good, good last day.

COREY I remain convinced that it is 100% possible, uh,

to get that world depth record here.

If you believe something's there, if,

if you believe it's worth doing, then you're gonna keep trying

to do it until, until you either do it or die.

BILL You know, the thing that happened this year

that was an epic, in my mind,

was that we discovered 20 kilometers of gigantic new tunnels,

the scale of which are unprecedented even in this cave.

There's no question about this project continuing.

It is a multi-decadal, multi-generational project

that has the allure because it is the hardest damn thing

going in exploration.

Hola!

Hola, my friend. Hola, my friend.

Good to be back in base camp.

Oh yeah.

Hi. How are you? Good.

I think it'll be good to,

to not put, put myself in this outfit every day.

Oh. Phew.

My back is probably the, is probably hurting the most right now.

PABLO Chevé's the first cave I've ever been to

and it was pretty awesome to experience it.

I love filming true expeditions

where you don't know what the outcome is gonna be.

We're not fabricating a story. This is, this is real exploration.

I mean I, I feel pretty damn lucky, you know?

Mmm. Oh jeez.

If we could have this at underground camp we'd still be down there.

BILL What I wanna do is be here for that special moment

when we realize the entire exploration from the entrance to the resurgence.

That, that will be special and that would be worth being here for.

And that will happen.

You know, whether it happens in one year,

two years or ten years it's gonna happen.

This will be the world's deepest cave.