and the most forbidding, Nepal's Mount Everest.

But every spring, hundreds of foreign tourists

arrive chasing a dream to stand atop the world.

(CHEERS)

SCOTT: Some are experienced climbers.

Many are not.

But all of them have this in common.

How many of the clients that you see coming to Everest

could do it without you?

Um, I would say zero.

-SCOTT: Zero? -Yeah.

-SCOTT: None of them? -None of them.

SCOTT: Jangbu Sherpa is a member

of the indigenous tribe known as the Sherpas,

the men who make climbing on Everest possible,

carrying the foreigners' luggage up the mountain,

laying a path for them to climb,

all but literally holding their hands.

It's a job the Sherpas were born to do,

their bodies and their work ethic

molded by centuries of living here.

But it's also a job that often kills them.

If something goes wrong, there's nothing you can do.

You just depend on your luck and then just go for it.

-Fate? -Yeah, fate.

SCOTT: Over the past five years,

32 Sherpas have been killed

as part of guided climbs on Everest.

Thirty-two among just a few hundred

who work there.

That makes the job of the Sherpa per capita

the most deadly on Earth.

Why would anyone do such dangerous work?

The thing is that,

there's no option, there's no choice.

-There's no other work? -No other work.

SCOTT: We met Sherpa Ang Tshering

at the staging point for any Everest climb,

base camp, 17,500 feet above sea level.

It is in these Himalayan mountains

where the Sherpas live,

in one of the highest and most remote communities

on the planet, separated from civilization

by a wall of mountains.

Alone at the top of the world,

they have virtually no other options for work.

What percentage would you say would rather not be here,

-risking their lives? -Eighty to 90 percent, easy.

-Nine out of every ten Sherpas -Yeah.

-would rather not be here? -Yeah.

It's trap. They always say,

"I'm not gonna come back next year,"

but you can see them find-- You'll find them here again now.

SCOTT: Because they need the money.

They need the money.

SCOTT: The dangers of the job

begin the moment the Sherpas leave base camp

and start their march into the clouds.

The long climb to the Everest summit starts

up that frozen glacier behind me called the Khumbu Icefall,

named for the massive blocks of ice perched overhead,

and poised to fall on climbers at any moment.

Time spent in the ice fall is borrowed time,

because the longer you're in it,

the more likely you are to be buried alive.

You can hear all the ice collapsing.

You just think, like, "Yeah, you don't want to stop.

Just keep moving, keep running...

-Running? -...as fast as you can."

On the way down, we do run.

The way you get safely through the ice fall is you go fast.

-You don't stop. -You don't stop.

SCOTT: Dr. Ellen Gallant,

an American cardiologist and mountain climber,

came to Everest as a client for the first time in 2014.

She remembers her first pass through the ice fall.

DR. ELLEN GALLANT: Every now and then,

there would be a really loud crack,

and you'd hear yelling,

and everybody's kind of looking around,

where is it coming from, what's coming down on us?

Stuff is going to come down, it happens every day,

and you just don't want to be at the wrong place

at the wrong time.

SCOTT: But foreign climbers like Dr. Gallant

face only a fraction of the risk of the Sherpas.

That's because the Sherpas don't have to pass through

the icefall once or twice, but up to 30 times,

back and forth through this valley of death.

The Sherpas are forced to make all those trips

to carry gear for their clients,

which often consists of dozens of bags

packed with the comforts of home.

Many pay to have their Sherpas carry everything

from imported food to heated tents,

to dining tables, yes, dining tables,

on the way up the mountain.

-Everything that goes up... -Yeah.

-has to go through the icefall -Through the icefall.

-...on your back. -Yeah. Yeah.

And on the backs of other Sherpas.

It doesn't make sense to me.

It shouldn't be too luxurious.

You know, that risks a lot of life.

SCOTT: During the 2014 expedition, dozens of Sherpas

were ferrying gear through the icefall

while their clients rested at base camp.

That's when it happened.

I was there at base camp in my tent

and heard a crash, and unzipped the tent,

looked toward the west shoulder of Everest,

and there was a... a massive plume of ice and snow.

It was like, from top, coming straight down.

-In one giant piece of ice. -Yeah.

How big?

It was the size of trucks, or even bigger.

SCOTT: Avalanches like this

can drop millions of pounds of solid ice in an instant.

After that, we hear screaming.

People screaming everywhere.

SCOTT: In the panic, Jangbu began searching for survivors.

I saw this guy on the left-hand side.

Just one guy.

-He was alive? -Yeah, he was alive.

Five of us, we started digging that guy out.

We saw the other guys underneath him, like they are...

You know, they're dead.

-Stacked on top of each other? -Stacked.

Yeah, stacked on top of each other.

SCOTT: Sixteen Sherpas were buried to death in ice.

The Sherpa community was left stunned.

At the same time, they were not surprised.

Every year, when these expeditions happen,

in every Sherpa household, every Sherpa's mind...

There's always the sense of dread.

When you see the faces of children before the fathers

climb Everest, they're almost resigned to the fact that,

you know, he may not make it back alive.

SCOTT: Norbu Tenzing should know.

His father was Tenzing Norgay, the very first Sherpa

to ever climb Everest, when he escorted

New Zealand climber, Edmund Hillary

up the mountain, in 1953.

NARRATOR: The top of the world has been reached.

SCOTT: Tenzing Norgay was the original Sherpa

success story, earning enough money that his children

could have options in life beyond mountaineering.

Today, his son Norbu lives and works in San Francisco.

But Norbu still worries about his people back home.

People's lives are being risked.

People are being taken advantage of.

Even if they're getting something out of it.

They're actually giving a lot more

than what they're getting.

Including, in some cases, their own lives.

Their own lives. Yeah.

Try explaining that to a widow.

SCOTT: Pacee Sherpa is one of the widows

of the 2014 avalanche.

Today, she lives in Nepal's capital, Kathmandu,

raising a little boy who was left without his father.

The boy was just weeks old when his father set off

to work on Mount Everest.

Before the climb, the father called home one last time.

(SPEAKING FOREIGN LANGUAGE)

(CRIES)

SCOTT: So, um...

And you say goodbye to each other?

Is that the last thing he said to you,

take care of your son?

SCOTT: But while Pacee's life was changed forever,

business as usual soon returned to Mount Everest.

Before long, a new batch of foreign climbers arrived

on the mountain looking to make another run at glory