Mount Everest.
Remote...
treacherous,
and with barely enough oxygen to survive.
A century ago, no-one had reached the summit.
NEWSREEL: 'This is what they came to see.
'This is what they came to find.'
The highest mountain in the world. It was there to be explored and hopefully there for the taking.
In this programme, Mount Everest summiteers
reveal how the mountain was conquered.
In 100 years, we discovered where it was, how high it was,
what the climate was for clothing,
the oxygen, everything.
From staying alive in the death zone...
Dan should definitely be dead!
..to beating some of the world's worst weather...
..brave pathfinders risked everything.
George Mallory's body was lying spread-eagled in the screed.
Now, hundreds of people stand on the summit every year.
OK. I'm gonna have to be quick
cos it's actually quite chilly!
I'm standing on Everest, by the way!
From tragedy to triumph.
And from base camp to the top of the world!
This is Mount Everest, then and now.
The Himalayas stretch 1,500 miles through northern Asia.
This cold, white world
is home to the planet's tallest peaks.
Here, one mountain is king -
Mount Everest.
When you get out there,
you don't realise just how enormous the thing is.
Everest is a monster!
At 8,848 metres,
it stands 5.5 miles above the sea.
It's a hulking mass, it really is.
Head and shoulders above every mountain around it.
And now, thousands of people have managed to achieve their dream
of climbing to the summit.
But in the early 20th century,
Mount Everest was an alien world,
completely unexplored.
Until British mountaineers stepped bravely into the unknown.
When I was 12, I met my cousin we called Uncle Hunch
and he told me about this huge mountain.
This was Howard Somervell, a remarkable man.
He was a double first at Cambridge.
He was a surgeon, a musician, a painter.
Uncle Hunch was also a climber.
In 1924, aged 34,
he joined one of the first British expeditions to Mount Everest.
So they really didn't know where the mountain was.
It was somewhere on the border between Nepal and Tibet.
In fact, the summit of Mount Everest sits exactly on the border
between the two countries.
The mountain has two main routes to the summit.
Along the south-east ridge from Nepal...
..and the north ridge from Tibet.
In 1924, Uncle Hunch and the British expedition
trekked 200 miles through Tibet
and approached Mount Everest
from the north.
They had hoped for an easy snow slope.
Instead, they saw a giant three-sided pyramid,
a rock and ice monster.
Uncle Hunch and the rest of the climbers
were used to European mountains
half the height of Everest.
For those first climbers, Everest was a new world.
They were in a very exotic and unhealthy country.
Half of them were suffering from dysentery.
They got frostbite.
It was a very, very tough mountain to crack
for those pioneers.
After weeks of climbing,
Uncle Hunch entered Mount Everest's "death zone".
It's an area of the mountain higher than 8,000 metres.
They call it the death zone because people die
simply because they are too high.
Because there's not enough oxygen to sustain life.
When you get to Everest base camp, there's only about half the oxygen available
that there is at sea level.
At the summit, there's only a third of the oxygen levels
that there are at sea level.
And those levels, we know,
are absolutely at the limits of what human beings can tolerate.
One of the reasons that we went to Everest
was to explore what that level was.
In 2007,
Professor Mike Grocott wanted to know the effect
of the lack of oxygen on the body.
So Mount Everest became his laboratory.
Mike's team measured oxygen levels at various heights.
Here, at 6,400 metres, three-quarters of the way up.
So we've just analysed Dan's arterial gas sample
and it's just astonishingly low.
You should be worried!
LAUGHTER
Still alive!
But the ultimate aim was for the team to take blood samples
in the death zone.
At an altitude of 8,382 metres
and with their oxygen masks removed,
the climbers were breathing some of the thinnest air in the world.
And there in a small shelter, four of us,
took arterial blood gas samples.
The colour is blue. It's very dark.
Arterial blood, coming from the heart, is usually bright red.
The uncharacteristic colour could only mean one thing -
severe oxygen depletion.
Whoa!
CO2, 3.50.
Dan should definitely be dead!
The measurements we made of oxygen in arterial blood
were really extraordinary.
There's no accounts of people with that sort of level
of oxygen in the blood who aren't unconscious or immediately after cardiac arrest.
The death zone's atmosphere is so dangerously thin,
now most climbers carry extra oxygen to help them survive.
We are there as visitors for a very short period of time.
Most of us can't really go there without some form of supplementary oxygen.
But back in the 1920s,
many mountaineers dismissed the need to carry extra oxygen.
It was almost seen as "not cricket".
You know, it's slightly cheating,
almost a drug-assisted ascent.
In 1924,
Howard Somervell had climbed to 8,570 metres.
He dreamed of being the first man to summit Everest.
But he had to make it up the treacherous North Ridge
in the freezing wind.
The technical area on the north side
is when you've got the first step, second step and the third step.
You're in a high-altitude environment
on tricky, technical terrain.
So it's not to be underestimated.
300 metres from the summit,
Somervell was forced to turn back.
When coming down, his larynx became frostbitten.
And the mucous membrane sloughed off,
blocked his airway and he sat down to die.
And he told me how he sat down
and did a Heimlich manoeuvre.
Squeezed his chest, and coughed up this frozen mucous membrane.
Uncle Hunch was able to breathe the icy air
and staggered on down the mountain to the North Col.
There, he met his friend, George Mallory.
George Mallory was a passionate mountaineer
who had tried to summit Everest twice before.
Now, on this expedition,
he was determined to succeed.
His name will forever be connected with Everest.
A very strong temperament,
a very driven individual.
Mallory came up with his rucksack full of oxygen cylinders,
ready to have an attempt with the "magic gas", oxygen.
After Somervell's failed attempt to summit,
Mallory saw an opportunity to make history.
Mallory said to him, "Somervell, I've forgotten my camera.
"Can I borrow yours?"
And Howard Somervell unwisely, he told me,
lent George Mallory his camera
and watched him as he headed up the mountain.
And that was the last he ever saw of him.
Mallory and his climbing partner, Sandy Irvine,
were last seen just 250 metres from the summit...
..before the peak was shrouded in thick cloud.
So, George Mallory, Sandy Irvine, did they summit?
Ah, who knows?
Howard Somervell had given Graham
a tantalising opportunity.
To solve the greatest mystery of the world's greatest mountain.
He said to me, aged 12, "If you could go and find that camera,
"you could prove whether my friends climbed it or not."
Was there a picture on that camera
of George Mallory standing on the summit,
waving his ice axe?
Who knows?
Next...
George Mallory's body was lying spread-eagled in the screed.
Was Mallory the first person to reach the summit?
And climbing Everest from the south. Then...
'A nightmare of spikes and chasms,
'a wrinkled and ravaged face.'
..and now.
50 million years ago,
Mount Everest was born.
The Indian sub-continent collided with Eurasia,
forcing land upwards and creating the Himalayas.
For millennia, the summit of Mount Everest was uncharted territory.
But in March 1924,
George Mallory and Sandy Irvine
embarked on a historic mission,
to be the first people to summit the mountain.
Mallory was carrying a camera given to him by Graham Hoyland's cousin,
Howard Somervell.
I became really obsessed
by trying to find this camera,
get the picture developed
and prove that Mallory had actually climbed the mountain first.
Graham began by retracing Mallory's steps.
So, here's the border between Tibet and Nepal.
Here's Mount Everest, the actual summit.
And Mallory would have come from their base camp up here,
from the north, through Tibet
around up to here to the North Col.
Up the ridge. And certainly got to this point.
Just a few hundred yards, really,
from the summit.
To this day, the outcome of Mallory and Irvine's push
to the summit is still disputed.
I think quite strongly, if I had to put money on it,
that Mallory made it to the summit.
I just can't imagine him turning round short of the summit,
even in the worst weather,
if there was any chance in his mind that he thought he could get there.
Like Mallory decades earlier,
in 1993, Graham climbed into Mount Everest's death zone.
I'm a very average climber
and as I chocked up those last few steps up to the summit,
I thought, you know, if I can do this,
surely George Mallory climbed Mount Everest.
Graham became the 15th Brit to reach Everest's peak.
And at that point, I thought he must have done it
and I set out wanting to prove that he'd done it.
When Graham returned to Everest in 1999,
there was a startling discovery.
George Mallory's body was lying spread-eagled in the screed.
It had been attacked, unfortunately, by birds.
But in his pockets were a bunch of strange things,
like nail scissors and a bill from his tailor!
But the one thing there wasn't
was a camera.
And so I started putting together what we knew.
And there was one crucial clue that came up later
which was the weather.
Mallory and Irvine were last sighted
just 250 metres from the summit
before they disappeared into a cloud.
Howard Somervell had taken readings down at base camp
of the air pressure.
And these were eventually unearthed
at the Royal Geographic Society.
Somervell's record of the weather was, "Fine still morning.
"Clouds began to advance up valley.
"Clouds behind and on Everest from 11 o'clock onwards."
We realised that George Mallory and Sandy Irvine
had been climbing up into a perfect storm.
When I put the clues together,
the low pressure, the perfect storm,
the limited oxygen, the poor clothing
and the lateness of the day,
I realised that Mallory probably hadn't climbed to the summit.
But it doesn't take anything away from their immense achievement.
This is the way humanity learns things,
by pioneers risking their lives.
For decades, every attempt to reach the peak failed.
Mount Everest seemed taller than ever.
NEWSREEL: 'St Paul's is 365 feet high.
One-fourteenth part of a mile.
'The highest mountain in the British Isles is Ben Nevis.
'The highest mountain in Europe is Mont Blanc.
'The highest mountain in the world is five and a half miles high.'
After the Second World War,
Nepal opened its borders to foreigners.
The 1950s offered an opportunity
to plot an entirely new route to the summit
from the south.
The scale of Everest is so huge,
it's easier to think of it in three sections.
The first section starts at base camp,
rises up the Khumbu Glacier
and into the Western Cwm.
The second section rises sharply up the Lhotse face
and ends on the South Col.
Then the third section.
From the South Col, up the Knife Ridge
and onto the summit.
In 1953,
the most famous expedition in mountaineering history
started its trek from the south
through Nepal.
The team included a Kiwi called Edmund Hillary
and Tenzing Norgay, a Sherpa.
After weeks in the foothills,
the British-led expedition team
laid eyes on the mountain for the first time.
NEWSREEL: 'So this is it.
'This is what they came to see.
'This is what they came to climb.'
That spring, they established a base camp.
Now, every year in the same spot,
base camp is home to dozens of tents from across the globe.
Here, climbers prepare for the ultimate adventure.
The first challenge
is one of the most treacherous stretches of the mountain.
The Khumbu Icefall.
'This advance party must advance through a frozen but burning forest.
'A forest as haunted by danger as any jungle in the world.
'A nightmare of spikes and chasms,
'a wrinkled and ravaged face,
'but a face that is always changing
'for the ice is always on the move.
'Cracking, rumbling, roaring.'
The Icefall is basically a 2,000-foot cliff
with a glacier falling over it.
There's giant ice chunks the size of a tower block, constantly moving.
It's a really frightening place.
You climb up through these moving blocks,
up the ladders tied together across huge crevasses.
'The ice has got to be made as safe as possible,
'though "safe" up here remains a comparative word.'
One year, an avalanche came down and nearly killed me and Brian Blessed.
The Khumbu Icefall is very technical
and it changes almost on a daily basis.
And you need to really have an awareness of your surroundings
to be able to negotiate that safely.
So we're crossing a ladder
and I'm panting in the background!
Ooh.
It's not about moving quickly.
Do you want me to pull the ropes for you?
OK.
It's about moving safely through an ever-changing environment.
Do you think so? You think I'm gonna enjoy it, do you?
Going over the chasm of death!
As well as negotiating ladders over deep crevasses,
climbers have to gently ease their way over snow bridges.
It's difficult to know, with some of these snow bridges,
which is the strong part...
..and where to stand.
And where to stop
and you might not just stop.
Now, that's a classic,
where you can see, you know, where you put your left foot,
eventually, that might get compromised.
So, uh... Yeah.
Ooh. Lots of slack rope.
Whoops!
In 1953,
the mountaineers hoping to be the first to summit Mount Everest
had successfully navigated the Icefall.
Next, they had to trek up the Western Cwm,
a vast flat area of endless snow and deep crevasses...
..only to be confronted by a giant ice wall -
the Lhotse Face.
It's a 1,200-metre wall of blue, glacial ice
that rises at severe angles of up to 45 degrees.
The climbers spent nine exhausting days carving out a route
up this icy face.
Hillary and Tenzing partnered up into one of the assault teams.
They would now be climbing so dangerously high
they had to use supplementary oxygen.
The 1953 Expedition
was based on months of painstaking research and preparation.
Some climbers acted as human guinea pigs in decompression chambers
to replicate the severe lack of oxygen.
'The oxygen mask is off.
'The air is getting thinner and thinner.
'At such heights when you're lacking oxygen,
'you may think you're normal,
'but you're not.
'You're moving in a dream,
'a dream that deludes and debilitates.
'Feel that now we're at the very summit of Everest,
'he's approaching unconsciousness.'
The modern oxygen system is delivered through
a very low-volume mask.
In the old days, there was the Russian fighter pilots,
the old Mig masks, that was a big Womble mask.
And these days, this is the very closest mask
to the Tornado pilots', actually.
Unfortunately, you do lose a little bit of the ability to talk.
Even now,
supplementary oxygen is still a limited resource.
If it runs out, then very quickly your body will deteriorate
and an acute amount of sickness
will be quickly followed by life-threatening situations.
In a very challenging environment,
you don't want to be incapacitated above 8,000 metres.
At 8,000 metres lies the South Col.
It's a pass between Mount Everest
and the fourth highest mountain in the world, Lhotse.
The South Col is the highest camp on the mountain.
It's a final opportunity to rest and recuperate
before the assault on the summit.
'The South Col. Camp eight.
'26,000 feet.
'A very hard place to get to
'and a very hard place to live in.'
When you get higher, you have a feeling of extreme vulnerability.
You are two or three days away from help and assistance
in a high-altitude remote environment.
Psychologically, that can really get to people.
'The South Col is no place for thoughts.
'Most of the time on the Col,
'a man hardly thinks at all.
'When he does, he usually thinks what bliss it would be
'to get down again.'
You need to make sure that you don't just lie down and go to sleep,
because you need fluid. You need to get a drink on the go
because if you get dehydrated,
you're much less likely to summit.
So you need to busy yourself in the tent and get on some energy.
The final approach to the summit
starts in the dead of night.
At 8,000 metres, climbers are at the mercy of the weather.
Making the decision to go for it is the difference between life and death.
It can take up to 16 hours to reach the peak,
so climbers need to ensure they have enough time to return safely.
'The South Col takes away everything.
'It also takes away his sleep unless he's using oxygen.
'Worst of all, it takes away his judgement.
'Hillary and Tenzing will need all their judgement tomorrow
'when they set out up that ridge,
'if the storm subsides.'
So why didn't we go to the summit last night?
We arrived in a storm,
we sat the storm out,
the entire night.
Yeah, massive gusts and snow coming in the tent. Yep.
Snow like and wind blowing in the porch
so we couldn't melt water. Did you get any sleep?
I think I got about five or ten minutes at one stage, yeah.
Oh. That's very generous!
What time is it now?
11.50. 11.50.
You'll be hopefully off tonight. We'll go about 9.30 tonight. Yep.
We've got about nine hours to just chill, rehydrate, eat.
And play cards! Play cards! Yes!
Oh. We didn't bring the cards! Oh.
'We had a lot of fun. You know, you're living at 8,000 metres.
Ooh, look at that. Beautiful.
Oh!
He's dropped it!
'I think that sense of camaraderie was probably quite important
'in the '20s and the '50s.'
Yes, you've got those people with quite big egos
who want to be the first.
But at the same time, you're all working for the greater good.
By 11.00am on May 29th 1953,
Hillary and Tenzing had begun their final push
to be the first to reach the summit
and were already out of sight.
'Everyone's thoughts are on what is happening
'on that knife-like ridge running up to the summit.
'But the climb today is beyond the reach of human eye,
'almost beyond imagination.'
100 metres from the summit,
Hillary and Tenzing were confronted by Mount Everest's final obstacle.
The Knife Ridge.
It's a dangerous section of steep, sharp, exposed rock
with perilous drops of more than 2,000 metres on either side.
'Well, I cut own the back of one ridge
'and round the back of another ridge.
'And the summit never seemed to be coming any closer!
'But finally, I cut down the back of another one
and saw that the ridge ahead dropped steeply away.
'So I looked up
'and there was the little rounded turn above us,
'and I knew it was the summit.'
All that was needed was a few more blows of the ice axe
and Hillary and Tenzing would be the first people
to stand on the summit of Mount Everest.
TIM: OK. I'm gonna have to be quick,
cos it's actually quite chilly.
I'm standing on Everest, by the way!
This is the peak of Mount Everest.
At 8,848 metres,
it's the highest place on the planet.
As Hillary and Tenzing celebrated in Nepal,
the news reached London
on a very historic day.
'June 2nd, 1953.
'People in London were excited, and with good reason.
'A queen had been crowned.
'And to add to the cheers,
'the newspapers gave an extra of extras.
'Men had climbed Mount Everest.'
Britain, as a whole, was absolutely delighted.
As a nation, we have always had an adventurous spirit.
You know, we've explored the world all over.
I think that lure of the highest mountain in the world,
it was there to be explored
and there for the taking.
Next...
After the triumph then,
the tragedy now.
The deadliest day in Mount Everest's history.
It was just utter, utter destruction.
The foothills of Mount Everest are home to the Sherpa people.
For generations, Sherpas had little contact with the outside world.
As Buddhists,
they believed a goddess lived in the mountain.
Not wanting to disturb her,
many did not set foot on Mount Everest.
Then, there was no Sherpa word for summit.
But now, climbers call their Sherpa porters and guides
"kings of the mountain".
They have been an absolutely integral part of climbing on Everest
from the very beginning.
You can see that they're faster and stronger at altitude
than certainly I am and most Westerners.
But little is known about their apparent superhuman physiology.
We're starting to see evidence
that their genetics have altered through evolution,
that they are naturally adapted
to perform well at high altitude where there's not much oxygen.
In 2013,
Professor Mike Grocott's Extreme Everest team
returned to the mountain.
On their first expedition in 2007,
they had already witnessed the superhuman Sherpas in action.
We couldn't have done the expedition without the Sherpas.
They were climbing alongside us,
but carrying substantially larger loads,
and apparently effortlessly.
So it was great to be able to come back in 2013
and really try and answer from the scientific perspective why that was.
At a height of 5,300 metres,
Mike's team built the world's highest laboratory
to compare Sherpas to lowlanders.
Bite on the mouthpiece.
How's your breathing?
There were some striking differences that start to explain
why they perform so much better at high altitude.
Go, go, go, go, go.
Keep it in.
The Sherpas' physiology is suited to producing the energy to power their bodies
even when oxygen is scarce.
In a Sherpa's muscles,
the parts of their cells that generate energy
are more efficient at using oxygen.
And at high altitude,
whilst lowlanders' blood flow slowed down,
the Sherpas' circulation was less affected.
Extreme Everest was almost entirely comprised of doctors and scientists,
many of whom had a background in critical care, intensive care,
so looking after the sickest patients in hospital.
Lack of oxygen in the bloodstream
is a major contributor to deaths in intensive care patients.
As a critical care expert,
Mike is hoping the Sherpas' superhuman ability
to adapt to altitude
could have benefits far beyond the slopes of Everest.
The real joy and challenge of the next few years
is looking at the huge set of data that we've accumulated
and trying to work out from those
what it is that identifies where people have adapted well
and if we could get our patients to do that,
then maybe, if you like, we can turn them into Sherpas!
Now, the superhuman Sherpas
are the backbone of every successful expedition up Mount Everest.
In the old days, I think people were probably a bit more purist
and they would probably be carrying their own gear
and nowadays, tents are set up for us by the Sherpas.
Some people have all their gear taken up to Camp Two
and you see people, actually,
without even carrying a rucksack on the mountain!
A Sherpa in front of them with their every need!
Sherpas prepare the mountain
by setting ropes, anchors and ladder bridges.
And they use their expert knowledge of its twists and turns
to help guide climbers to the top.
I couldn't possibly have climbed Everest without them.
You know, quite seriously, without Ang Passang and Kami Tchering,
not in a million years.
In 1993, Rebecca Stephens became the first British woman
to climb the world's highest mountain.
There was this tremendous feeling of togetherness
and I'll remember it until I breathe my last breath.
That year, the Nepalese and Chinese authorities
had begun to increase the number of climbing permits.
I think through the '90s, into the 21st century,
we are now in the commercial era on Everest.
In the 1970s,
just 562 people climbed Mount Everest.
Over the last decade,
nearly 4,000 people have reached the summit.
Nepal is a poor country
and it desperately needs foreign exchange.
So it has to try and make money out of the Himalayas
and in particular, Mount Everest, which is a real cash cow.
So, to climb Mount Everest, your tickets would cost
anything from 35,000 US dollars
all the way through to 120,000 US dollars or more.
Throughout the 21st century,
climbing Mount Everest allowed the Sherpa people to flourish.
Now, the climbing industry is worth over £1.5 billion
to Nepal every year.
But Sherpa livelihoods and lives are at the mercy of the mountain.
On April 18th, 2014
warm weather triggered a series of avalanches
near Mount Everest's Icefall.
The Icefall is a very dangerous part of Mount Everest.
And whereas we Westerners might only go through it two or three times,
the Sherpas have to carry the tents and equipment
and food and everything through dozens of times.
16 Sherpas lost their lives.
When 16 died in one event,
for the sake of looking after Westerners on the hill,
I think it struck a very uncomfortable chord
about the dangers that they were being exposed to.
During the 20th century,
brave Sherpas were at the heart of Mount Everest's success story.
Now, there was a grim realisation
that being a mountaineering Sherpa
was one of the most dangerous jobs in the world.
On April 25th, 2015,
a huge earthquake hit Nepal.
It's one of the worst natural disasters in the country's history.
Tim Mosedale was one of hundreds of climbers on Mount Everest
when the earthquake struck.
We arrived at Camp One and we radioed down to base camp
and we heard that the middle of base camp had been obliterated.
Go! Go!
The earthquake had also triggered avalanches on Mount Everest.
One of them swept down the mountain
and thundered towards base camp.
359 people were waiting to climb the mountain.
When you're at the base camp,
you think of Everest as being safe.
But the forward draught from the avalanche swept through the camp
and rocks flying everywhere.
And if you were in its path, you know, that was it.
It was just utter, utter destruction.
Nearly 9,000 people died across Nepal.
At base camp, 19 climbers lost their lives.
Three of them were Sherpas on Tim's expedition.
They left behind nine kids.
And they were working on the mountain
to provide for their families.
The 25th of April, 2015,
is the deadliest day in Mount Everest's history.
People were questioning, really, what was going on
and was Everest really worth it?
Next...
Mount Everest becomes a deadly tourist trap.
I think the overcrowding has made Mount Everest actually more dangerous
than it was before.
People are just lambs to the slaughter.
Why are climbers dying in queues to the summit?
A century ago, the summit of Mount Everest was an unknown wilderness,
untouched by human hand.
Now, the highest point on the planet
has been transformed...
..into a tourist trap.
On May 22nd, 2019,
this photograph revealed the reality of climbing the mountain.
Waiting for hours in a queue.
Too many people, stood for too long, in a very challenging environment.
That picture was taken on one day
and it would be like that on one day in 365.
For the rest of the year, one of the elements can make a summit impossible.
Wind.
At 8,848 metres
the summit of Mount Everest is exposed to the extremes
of Earth's weather.
At the top of the world, the wind is wild.
So it being nearly 9,000 metres,
Everest pokes up into the Jet Stream
which is a force unto itself.
Freezing winds batter Mount Everest
at speeds up to 175 miles per hour.
On the South Col, the last stop on the route to the summit,
the wind can be so cold and so strong,
climbers are trapped in their tents.
But every year in late May,
the approaching monsoon brings a rare window of opportunity.
The monsoon is such a massive weather system,
effectively, it nudges the Jet Stream slightly.
And that might displace it upwards
or put a fold in it,
or it might just alter the Jet Stream across Everest.
And that means that we're then not subjected to
the huge winds that we would otherwise experience.
When the wind drops, there are weather windows.
It might be anything from a 12-hour window
to a four, five, six, even 11 or 12-day window,
where you're looking for benign conditions
where we can then operate safely on the mountain.
For decades, climbers had little idea
when a weather window would open.
Now, most climbers only summit during weather windows.
One of the great things that we've got nowadays
is the weather forecasting that comes in.
And it's getting more and more accurate.
When a weather window does open,
hundreds of climbers converge on the summit.
People are opting for that optimum day,
so you do get this problem of overcrowding.
You're moving fairly slowly anyway.
And if you're in a queue
and so you are moving even slower,
and the oxygen is still flowing,
your life is basically being jeopardised.
And you could find yourself very high on the mountain,
becoming extremely exhausted and hypoxic,
which is lack of oxygen to the brain,
and you could die as a result.
2019 was one of the deadliest years in Mount Everest's history.
11 people lost their lives.
Many of the deaths on Everest
occur high, particularly high on the south-east ridge.
When climbers have to wait in queues,
they risk running short of oxygen
and may not have enough left for the journey down.
We do have that problem of being somewhere
where, as human beings, we're not naturally supposed to be.
Without artificial support of oxygen, people die.
I think the overcrowding has made Mount Everest
actually more dangerous than it was before.
How that might be resolved, could there be a code of conduct
or even if there should be a rescue service on Everest,
which is anathema to a traditional mountaineering way of thinking,
that you're self-supporting
and the last thing you'd want to do is get on a mobile and ask for help!
I think something has to be done
to try and regulate this,
otherwise, people are just lambs to the slaughter.
Mount Everest's epic tale
from tragedy to triumph
has come full circle.
In this programme, we've discovered how brave pioneers died
because they lacked the scientific knowledge to climb the mountain.
But by the 1950s,
mountaineering had evolved.
Climbers had learned how to breathe, how to stay warm
and how to find a safe way to the top.
I think Mount Everest is an incredible symbol of human progress.
In 100 years, we discovered where it was, how high it was,
what to climb it with, your clothing, the oxygen.
Everything.
By the end of the 1980s,
just 284 people had stood on the summit.
Now, over the last decade,
nearly 4,000 climbers have made it to the top.
It's become now so simple
that a 13-year-old boy can climb Mount Everest.
It's more accessible. That's not a bad thing.
More people will have the opportunity to climb it.
That's not a bad thing. But it is a very, very different experience.
We can never turn back the wheel.
Now, from natural disasters to overcrowding,
Mount Everest is still one of the most inhospitable,
daunting and dangerous places on the planet.
But the mountain will always stand proud,
a breathtaking symbol of our spirit of adventure,
our need to explore...
..and our desire to conquer.
Mount Everest hasn't changed itself.
It's still the highest mountain in the world,
it's still a beautiful wilderness.
Now, people just pour up it in hundreds.
But essentially itself, it's indifferent to humanity.
It's still the same mountain.
Subtitles by Red Bee Media