True scale. One pixel is 12.5 centimetres. Scroll upward to climb. Coming down is the other half.
The floor of the atmosphere. Half the mass of the air sits within 5,500 m above this line.
Most weather is made and finished in this band.
The altitude at which the body starts to notice.
Most of the seven continental high points stand inside this band.
No recovery happens here. Time spent is damage taken.
408,000 m. You would have to stack forty-six Everests to reach it. It circles the Earth every ninety minutes, and the crew see sixteen sunrises a day.
There is still a trace of atmosphere up there. Without regular boosts it would fall.
100 km. Calling this the beginning of space is an agreement, not a physical fact. The atmosphere does not end here; it thins outward for hundreds of kilometres more.
The boundary was not discovered. It was decided.
Most meteors burn up between 75,000 and 100,000 m. Something the size of a grain of sand meets the air and becomes light.
On 24 October 2014 Alan Eustace jumped from 41,419 m. He went up under a balloon in a pressure suit, with no capsule.
On 14 October 2012 Felix Baumgartner stepped off at 38,969 m. The air was thin enough that he passed the speed of sound in free fall.
They rise to around 35,000 m. Close to eight hundred are launched worldwide every day. A large part of every forecast comes from them.
Between 20,000 and 30,000 m sits the layer that stops ultraviolet light. This thin band of gas is what keeps life possible at the surface. Compressed to surface pressure it would be 3 mm thick.
Mars. 21.9 km above the datum. It is so wide that from the summit the mountain falls away below the horizon.
At about 19,000 m the pressure falls to 6.3 kPa — the pressure at which water boils at body temperature. No amount of oxygen helps here. Your own body fluids begin to boil.
The boundary beyond which pressurised oxygen alone is not enough.
In 1973 a Rüppell’s vulture was drawn into an airliner engine at 11,300 m. It remains the highest confirmed bird flight.
Challenger Deep is 10,935 m. Drop Everest into it and 2,086 m of water still cover the summit. The lowest place on Earth is farther away than the highest one.
Far more people have stood at the lowest point than have walked on the Moon.
10,668 m. The cabin is pressurised to about 2,400 m. Outside the window it is −55 °C.
The summit of Everest — the point on the surface farthest from sea level. Almost nobody stays longer than twenty minutes.
The rock at the summit is Ordovician limestone. It formed roughly 470 million years ago on the floor of a shallow, warm sea, out of shell fragments and pieces of trilobite. The stone at the highest place on Earth was made under water.
The layer is called the Qomolangma Formation. Marine fossils come off the summit.
At 11:30 in the morning Edmund Hillary and Tenzing Norgay stood on the summit. Neither ever said who stepped there first. They said only that they had climbed together.
On 8 May 1978 Reinhold Messner and Peter Habeler reached the summit breathing only what was there. Most of the medical establishment had held it to be impossible. The margin came from a fact: the real pressure on the summit is about 7 % higher than the standard atmosphere predicts.
Measured 1981: 337 hPa · standard atmosphere: 314 hPa
On 16 May 1975 she became the first woman to reach the summit. Twelve days earlier she had been dug out of an avalanche by her Sherpa team.
On 17 February 1980 Krzysztof Wielicki and Leszek Cichy climbed it in winter. The wind on the summit that day was over 100 km/h.
8,840 m in 1856. 8,848 m in 1955. 8,850 m in 1999. 8,848.86 m in 2020. The number moved because our instruments moved, not the peak. Whether to include the snow or stop at the rock had to be agreed before anything could be measured at all.
The Himalaya does rise — a few millimetres a year. It is worn down at the same time.
A large share of eight-thousander accidents happen on the descent. At the top the goal disappears, half the oxygen is gone, and the body is already damaged. A climb ends when you are back.
Scroll downward now. Getting down is the other half.
George Everest was Surveyor General of India and never saw this mountain. When his successor proposed attaching his name to it, he objected — it could not be written in the local script and could not be pronounced. The name stuck anyway.
Chomolungma in Tibetan. Sagarmatha in Nepali. Both belong to people who have lived in sight of it.
In 1852 Radhanath Sikdar, a computer in the Survey of India, finished the calculation and reported that this peak was the highest in the world. He was Bengali, and he worked with numbers rather than in the field. The mountain was named after the man who employed him.
The first figure came out at exactly 29,000 feet. The story goes that it was published as 29,002 so it would not look rounded.
The Indian plate is driving under the Eurasian one and pushing the Himalaya up about four millimetres a year. Erosion takes most of it back, so the net gain is roughly a millimetre. It has risen very slightly while you read this sentence.
The 2015 earthquake actually lowered Everest by a few centimetres.
Fifty million years ago India was an island, and the Tethys Ocean lay between it and Asia. As India moved north the sea closed, and the limestone that had settled on its floor was driven upward. The marine fossils at the summit are the last of that ocean.
That the mountain came out of the sea is not a metaphor.
8,810 m, installed in 2022. Summit-level pressure is now measured rather than estimated.
On 22 May 2019 climbers backed up on the final ridge. Eleven died that season, many of exhaustion and spent oxygen. Waiting in the death zone is not simply waiting.
This is where the cost of waiting is paid in oxygen.
A twelve-metre rock band just below the summit. In 2017 it was confirmed gone, most likely in the 2015 earthquake.
Lower than Everest and far harder. It was not climbed in winter until 2021.
A serac collapsed during the descent and cut the fixed ropes. Eleven people died. Most accidents happen on the way down, not the way up.
1 August 2008 · 11 dead
Believed to be the world’s highest until 1852. By convention expeditions stop a few metres short of the true summit.
It shares the South Col with Everest. Its south face is still barely climbed.
A clean four-sided pyramid with steep ridges on every side.
8,430 m. A weather station was installed here in 2019.
Around two hundred bodies remain on Everest. Bringing one down costs more than seventy thousand dollars, and people have died trying. Leaving them is not callousness. It is arithmetic.
Nothing is written here about an afterlife.
Regarded as the most straightforward eight-thousander, and therefore the most climbed.
For thirty years from 1808 it was believed to be the highest mountain in the world.
The name is Sanskrit for “mountain of the spirit”.
Its Rupal Face rises 4,600 m — the largest mountain wall on Earth.
The first eight-thousander ever climbed, and the one with the highest ratio of deaths to summits.
Also called Hidden Peak.
A long summit ridge; many parties have turned back at a false summit.
Considered among the more forgiving of the eight-thousanders.
The lowest of the fourteen, and the only one entirely inside China.
Above 8,000 m the body cannot repair itself. Sleep does not restore, food is not digested, rest does not help. Time is damage. “Slow and steady” is not a strategy at this altitude.
Oxygen pressure here is about 30 % of sea level.
A season leaves tens of tonnes of rubbish: oxygen bottles, tents, rope, human waste. Nepal now holds a deposit and requires each climber to carry eight kilograms down. Even so, most of what is above the death zone stays there.
The rubbish in the highest place is the hardest to remove.
7,952 m. The highest mountain that is not an eight-thousander. Forty-eight metres kept it off the list of fourteen, and so it has been climbed only a handful of times. It is not height that draws people. It is the list.
The eight-thousand line is an artefact of the metric system. In feet, different mountains would be famous.
At two litres a minute the summit feels like about 5,840 m. At four litres, 4,037 m. The mountain does not get lower; you carry the air up with you.
Computed from the measured summit pressure of 337 hPa.
7,920 m. The last camp, already at the threshold of the death zone. Most parties leave around midnight.
7,885 m. Among the highest peaks that fall short of eight thousand metres — and therefore almost never climbed.
7,816 m. In 1965 American and Indian intelligence tried to place a plutonium-powered listening device here to watch Chinese nuclear tests. A storm forced the team to leave it partway up. When they returned the next year it was gone. It has never been found.
Water off this mountain runs into the Ganges.
7,800 m. On 21 May 2013 a helicopter lifted a stranded climber from this altitude. The air is thin enough that the rotor is close to the limit of producing lift at all.
21 May 2013
Aviation medicine calls it the time of useful consciousness. Lose your oxygen suddenly at 7,600 m and you have three to five minutes in which you can still make a decision. At 9,000 m it falls under a minute. What defines this kind of hypoxia is that you do not notice it happening.
The first thing pilots are taught is to trust someone else. Your own judgement is already damaged.
7,546 m. The slopes are gentle enough that some people ski down from the summit.
7,495 m. The highest point in Tajikistan; under the Soviet Union it was Communism Peak. The names of mountains change with the government.
7,492 m. The highest point in Afghanistan. It was unreachable for decades because of war.
7,439 m. The highest of the Tian Shan, and the most northerly seven-thousander, which makes it the coldest.
Bar-headed geese have been recorded at 7,290 m. They go over the range rather than around it. To beat your wings where the oxygen is a third of sea level takes lungs and haemoglobin far more efficient than ours.
They do it in one push. There is no acclimatisation period.
7,200 m, midway up the Lhotse Face. Most climbers start using oxygen here.
7,161 m. Mallory named it. It means “daughter”.
7,134 m. In 1990 an avalanche destroyed a camp and killed forty-three people — the worst single accident in mountaineering.
13 July 1990 · 43 dead
7,045 m. More a walk than a climb, and from it the whole north face of Everest is laid out.
7,020 m. The gateway of the northern route, and reckoned the windiest stretch on the mountain.
6,961 m. The highest mountain outside Asia.
6,893 m. The highest volcano on Earth. There is a crater pool near the summit, generally counted as the highest lake in the world.
6,812 m. The name means “mother’s necklace”. Two kilometres lower than Everest and far steeper.
6,768 m, the highest point in Peru. The equatorial bulge and the altitude combine so that gravity on this summit is the weakest anywhere on the surface. Someone who weighs 100 kg at the pole weighs 99.5 kg here.
Gravity is not a constant. It is a question of where you are standing.
The Himalayan jumping spider lives in rock cracks at 6,700 m. Almost nothing grows at that height, so there is nothing to eat. It feeds on insects blown up from below — an ecosystem living entirely on what the wind delivers.
The highest altitude at which any animal is known to live permanently.
6,638 m. Sacred to four religions, and nobody has climbed it. That was decided rather than attempted. It is the most conspicuous unclimbed peak on Earth.
Moss grows at 6,480 m. There is no soil and the air stays below freezing; it lives on the few hours a day when the rock itself warms up.
6,476 m. The highest of Nepal’s designated trekking peaks.
6,438 m. The mountain visible from anywhere in central La Paz.
6,400 m. At the head of the Western Cwm; in practice the advance base.
6,400 m. On the north route, yaks carry loads this far. It is the highest altitude yaks work.
Earth bulges at the equator. So the point on the surface farthest from the centre of the planet is not Everest but Chimborazo, near the equator. Its summit is 6,384 km from Earth’s centre — more than two kilometres farther out than Everest’s.
6,263 m above sea level · farthest point from Earth’s centre
6,190 m. It rises 5,500 m from its base — the greatest rise of any mountain above sea level. Its latitude makes it feel far higher than it is.
6,189 m. The entry-level six-thousander, used by Everest expeditions for acclimatisation.
6,065 m. The first camp above the icefall.
A glacier moving about a metre a day and tearing itself open as it goes. On 18 April 2014 a serac collapsed and killed sixteen people. The season was abandoned.
16 dead · all Nepali high-altitude workers
5,895 m. More than 80 % of the summit ice has gone since 1912. It is ice 340 km from the equator, and what remains is not expected to last.
Africa’s high point · a volcano
5,644 m. The nearest viewpoint from which the summit is fully visible. From base camp itself, Everest cannot be seen at all.
5,642 m. Counted as Europe’s highest point. A dormant volcano.
5,610 m. The highest point in Iran and the highest volcano in Asia. Sulphur still vents at the summit.
5,500 m · 506 hPa
5,421 m. The highest ski resort in the world used to be here. People skied on a glacier eighteen hundred years old. In 2009 the glacier finished melting — sixteen years earlier than predicted.
The lift towers are still standing. Only the snow is gone.
5,364 m on the south side. In season more than a thousand people are here. From this point 3,485 m remain.
About a third of those who have died on Everest were Nepali high-altitude workers. They fix the ropes, place the ladders and carry the oxygen. The summit photograph usually shows the client.
18 April 2014, Khumbu Icefall — 16 dead, all Nepali.
A commercial expedition runs between thirty and a hundred and ten thousand dollars. The permit alone is eleven thousand. A Sherpa climbing the same mountain earns a fraction of that for the season.
Same mountain, same day, same rope. Different price.
5,359 m. Among the highest passes a vehicle can cross. The sign at the top claims a higher number; the survey says this one.
Sign: 5,602 m · surveyed: 5,359 m
5,357 m. With Kala Patthar, one of the viewpoints from which the summit can be seen. Six turquoise lakes lie below it.
5,150 m. The Tibetan-side base camp, and you can drive to it. Reaching the south side takes eight days on foot.
5,137 m. Where the ark is said to have come to rest. It rises 4,300 m above the plain — among the greatest such rises anywhere.
La Rinconada, Peru. Fifty thousand people live at 5,100 m. The ceiling for permanent human acclimatisation is thought to be around 5,300 m. Above that, acclimatisation never finishes.
The town has the highest recorded rate of chronic mountain sickness in the world.
5,054 m. The mountain to which Prometheus was said to be chained.
4,892 m. The high point of Antarctica. The nearest settlement is 1,200 km away.
4,884 m. The highest point near the equator; its glaciers are all but gone.
The summit of Mont Blanc is snow, not rock. It is surveyed every two years: 4,807.81 m in 2021, 4,805.59 m in 2023. The height of the mountain depends on that year’s wind.
The rock summit sits at 4,792 m and barely moves.
4,634 m. The second highest in the Alps. Europe’s highest mountain hut stands at 4,554 m.
GPS assumes the Earth is a smooth ellipsoid and measures from that surface. Elevation above sea level is measured from the geoid. The two references differ by up to about 100 m depending on where you stand, so in the same spot your GPS and your map disagree. Both are right. They are measuring different things.
A barometric watch is different again. When the weather changes, your altitude changes while you stand still.
4,478 m. On the first descent in 1865 a rope broke and four men died. People say the golden age of alpinism ended that afternoon.
14 July 1865 · 4 dead
4,421 m. The highest point in the contiguous United States, a day from the lowest.
4,392 m. It carries more glacier than any other peak in the contiguous United States. It is visible from Seattle and is considered the most dangerous volcano in the country.
4,302 m. There is a road and a railway to the summit. “America the Beautiful” was written up here.
4,207 m above sea level. Measured from its base on the ocean floor it is 10,211 m — taller than Everest. More than half the mountain is simply under water.
Base to summit: Mauna Kea 10,211 m · Everest 3,000–5,000 m
4,169 m. By volume the largest mountain on Earth. Its own weight has pressed the sea floor beneath it down by eight kilometres.
4,167 m. The highest point in North Africa. From the edge of the Sahara you can see snow on it.
4,158 m. Europe’s highest railway station sits at 3,454 m — they tunnelled through the mountain to build it.
4,150 m. The highest city in the world with more than a million people.
3,967 m. The north face is 1,800 m high and was called the murder wall. It was not climbed until 1938.
3,867 m. Where expeditions receive a blessing before going up. It burned in 1989 and was rebuilt.
3,812 m. The highest lake in the world that large boats can work. In the early twentieth century a British-built steamship was taken apart, carried up by mule, and reassembled here.
The water is deep enough that it keeps the shore warmer in winter.
3,798 m. The highest point in Austria.
3,794 m. An active volcano in Antarctica with a lava lake in its summit crater. It is the southernmost active volcano on Earth.
3,776 m. Japan’s highest point, and an active volcano.
Aoraki / Mount Cook was 3,764 m. In December 1991 the summit collapsed, twelve million cubic metres came down, and the mountain lost ten metres. A resurvey in 2013 put it at 3,724 m.
The scar is still eroding. The height keeps falling.
3,715 m. The highest point in Spain. Measured from its base on the sea floor it is over 7,500 m.
870,000 people live at 3,656 m. Tibetans carry genetic adaptations to low oxygen.
A variant of the EPAS1 gene, thought to have come from Denisovans.
3,440 m. The Sherpa town on the way to Everest. Most expeditions stop here for two days to acclimatise.
3,399 m. The Inca capital. A good share of the travellers who arrive here spend their first day with a headache.
2,962 m. Germany’s highest point. The border runs across the summit, so Germany and Austria share it.
2,930 m. The most active volcano in Indonesia. The name means “mountain of fire”, and tens of thousands live on its flanks.
2,917 m. The highest point in Greece, and the home of the gods. The first recorded ascent was in 1913.
2,850 m. It sits on the equator and averages 14 °C all year. Altitude, not latitude, sets the climate.
2,744 m. The crater lake at the top is 373 m deep at its deepest.
2,640 m. Among the highest capitals in the world with eight million people.
Above 2,500 m acute mountain sickness appears: headache, nausea, broken sleep. It has little to do with fitness, and the young are if anything more prone to it. There is one reliable treatment — descend.
About one in four people have symptoms at 3,000 m.
2,430 m — lower than most people picture it. Cusco, in the valley below it, is a thousand metres higher.
2,240 m. The 1968 Olympics were held here. Sprint and jump records fell in a heap; the distance events collapsed. The same air did both.
1968 · the long jump record stood for 23 years
2,228 m. The highest point of mainland Australia, with a sealed path most of the way.
1,947 m. The highest ground in South Korea.
1,917 m. On 12 April 1934 a gust of 372 km/h was measured on this summit. For more than sixty years it stood as the highest surface wind speed ever recorded. It came off a mountain under two thousand metres.
Being low does not make it safe. More than 160 people have died here.
1,915 m.
1,609 m above sea level. The thinner air means less drag, and a batted baseball carries about 9 % further. That is why the outfield here is larger than anywhere else. Altitude rewrites the record book.
The stadium keeps its balls in a humidor to take some of the bounce back out.
1,345 m. Britain’s highest point, and the summit is in cloud most of the year.
1,281 m. In AD 79 it buried Pompeii. The pyroclastic flow moved at over 100 km/h, and people died of the heat rather than the ash.
AD 79 · 600,000 people now live in the danger zone
The base of a cumulus cloud is set by the gap between air temperature and dew point — roughly (temp − dew point) × 125 m. A cloud is the height at which cooling air can no longer hold its water.
Cloud base is not a fixed altitude. It is that day’s humidity.
1,086 m. The flat top is what is left after nearly six hundred million years of erosion. The landform is far older than the Himalaya.
1,085 m. The highest point in Wales, with a mountain railway to the summit. Hillary’s expedition trained here.
A drop of 979 m. Much of the water turns to mist before it lands.
It stands 348 m above the plain. Far more of it lies buried than shows.
Burj Khalifa, 828 m. Nothing human-made goes higher. And 8,000 m still remain.
Completed 2010 · 828 m
634 m — a number chosen because it reads as the old province name Musashi.
632 m. Second only to the Burj Khalifa.
555 m.
426 m. In antiquity this was the end of the world — one of the pillars said to carry the warning not to go further.
396 m. A block of granite at the mouth of Rio’s bay. A cable car has run to the top since 1912.
324 m. The tallest structure in the world until 1930.
262 m, a hill in the middle of Seoul. With the tower on top it reaches 480 m.
Mount Wycheproof in Australia. 148 m, rising 43 m above the plain around it. It is officially registered as a mountain. What counts as a mountain is settled by paperwork, not by landform.
138.8 m. For 3,800 years it was the tallest thing humans had built. What finally passed it was the spire of Lincoln Cathedral.
93 m including the pedestal.
Twenty million people live at a mean elevation of 4 m. A one-metre rise in sea level puts much of the country under water.
The highest natural ground is 2.4 m. That is the highest place in an entire nation.
Mean elevation 2 m. The highest ground in the country is lower than this sentence is long.
Everest’s height is measured from sea level. But there is no sea under the Himalaya. We assume an imaginary ocean surface — the geoid, computed from Earth’s gravity field — continues beneath the continent, and count from that.
The geoid departs from the reference ellipsoid by up to about 100 m depending on where you stand.
−6.76 m. The lowest point in continental Europe, and it used to be a lake. The water was pumped out. It is the lowest place people have made.
Its surface lies 28 m below sea level. It is the largest lake on Earth, and though we call it a sea it connects to none.
The lowest point in North America. Mount Whitney’s summit is 136 km away and 4,507 m higher.
The lowest exposed land on Earth. The surface drops nearly a metre a year, so this number will be wrong in a few years.
−430 m · falling
The sea and space are dangerous because we do not know them. A mountain is different. Everest is fully surveyed, mapped, strung with fixed rope, and climbed more than ten thousand times. People still die on it.
Everyone who died here chose to go. That changes the shape of the mourning. We are not mourning an accident. We are mourning a decision.
Nobody stays on a summit. The point of a mountain is not the top; it is the return.