Everest is the highest mountain on Earth (as measured from sea level). The summit ridge of the mountain marks the border between Nepal and Tibet. In Nepal, the mountain is called Sagarmatha (सगरमाथा, Sanskrit for "Forehead of the Sky") and in Tibetan Chomolangma or Qomolangma ("Mother of the Universe"), pronounced in Chinese 珠穆朗玛峰 ( pinyin: Zhūmůlǎngmǎ Fēng). Although named in honour of Sir George Everest, the popular pronunciation of Everest (EV-uh-rist, IPA: [ˈɛvərist]) is different from how Sir George pronounced his own last name (EV-uh-rest, IPA: [ˈɛvərɛst]).
The mountain received its international name Everest after Sir Andrew Waugh , the British surveyor-general of India, named it after his predecessor, Sir George Everest.
Radhanath Sikdar, an Indian mathematician and surveyor from Bengal, was the first to identify Everest as the world's tallest peak in 1852 through trigonometric calculations based on measurements made with theodolites from 150 miles away in India. Some believe that the peak should have been named after Sikdar, not Everest. Prior to its survey and naming it was known as Peak XV to the survey team.
The mountain is approximately 8,850 m (29,035 feet; almost 5.5 miles) high, although there is some variation in the measurements (the Nepal government has not officially recognised this measurement, and the height of Everest is still considered 8,848 m in Nepal).
It was first measured in 1856 to have a height of 29,000 feet, but declared to be 29,002 feet high. The arbitrary addition of 2 feet reflected the sentiment at the time that an exact height of 29,000 feet would be viewed as nothing more than a rounded estimate.
In the 1950s an Indian survey made closer to the mountain also using theodolites gave another often quoted figure of 29,028 feet. Today's generally accepted value of 8,850 m (29,035 feet) was obtained via GPS readings from a device placed on the summit by the USA in 1999. Everest is still growing due to the plate tectonics of the area, adding a few centimetres per year to the height.
Everest is the mountain whose summit attains the greatest distance above sea level. Two other mountains are sometimes claimed as alternative "highest mountains on Earth." Mauna Loa in Hawaii is highest when measured from its base; it rises over 9 km (30,000 feet) when measured from its base on the mid-ocean floor, but only attains 4,170 m (13,680 feet) above sea level. The summit of Chimborazo in Ecuador is 2,168 m further from the Earth's centre (6384.4 km) than that of Everest (6382.3 km), because the Earth bulges at the Equator. However, Chimborazo attains a height of 6,310 m above sea level, by which criterion it is not even the highest peak of the Andes.
The deepest spot in the ocean is deeper than Everest is high: the Challenger Deep, located in the Mariana Trench, is so deep that if Everest were to be placed into it, it would have almost a mile of water covering it.
Mt. Everest has two main climbing routes, the southeast ridge from Nepal and the northwest ridge from Tibet. Of the two, the southeast ridge is technically easier and is the most frequently used route. It was the route used by Hillary and Tenzing in 1953. This was, however, a route decision dictated more by politics than by design as the Tibetan border was closed to foreigners in 1949.
The majority of attempts are undertaken during April and May before the summer monsoon season. A change in the jet stream at this time of year also reduces the average wind speeds high on the mountain. While attempts are sometimes made after the monsoons in September and October, the additional snow accumulated from the monsoons adds to the difficulties.
The ascent via the southeast ridge begins by a trek to Base Camp at 5,380 m (17,600 ft) on the south side of Everest in Nepal. Expeditions typically fly into Lukla (2,860m) from Kathmandu and then hike to Base Camp, which typically takes six to eight days, allowing for proper altitude acclimatization in order to prevent altitude sickness. Climbing equipment and supplies are carried by yaks, dzopkyos and porters to Base Camp on the Khumbu Glacier. When Hillary and Tenzing climbed Everest in 1953, they started from Jiri which, nowadays, takes five to eight days to reach Lukla.
Climbers will spend a couple weeks in Base Camp, acclimatizing to the altitude. During that time, Sherpas and some expedition climbers will setup ropes and ladders in the treacherous Khumbu Icefall. Seracs and shifting blocks of ice makes the icefall one of the most dangerous sections of the route. Many climbers and Sherpas have been killed in this section. To reduce the hazard, climbers will typically begin their ascent well before dawn. Once sunlight reaches the icefall, the danger increases very substantially. Above the icefall is Camp I or Advanced Base Camp (ABC) at 6,065m (19,900 ft).
From Camp I, climbers make their way up the Western Cwm to the base of the Lhotse face, where Camp II is established at 6,500m (21,300 ft). The Western Cwm is a relatively flat, gently rising glacial valley, marked by huge lateral crevasses in the centre which prevent direct access to the upper reaches of the Cwm. Climbers are forced to cross on the far right near the base of Nuptse to a small passageway known as the "Nuptse corner". The Western Cwm is also called the "Valley of Silence" as the topography of the area routinely cuts off any wind from reaching the climbing route. The high altitude and a clear, windless day can make the Western Cwm unbearably hot for climbers.
From Camp II, climbers ascend the Lhotse face on fixed ropes up to a small ledge at 7,470 m (24,500 ft). From there, it's another 500 metres to Camp IV on the south col at 7,920 m (26,000 ft). From Camp III to Camp IV, climbers are faced with two additional challenges: The Geneva Spur and The Yellow Band. The Geneva Spur is an anvil shaped rib of black rock named by a 1952 Swiss expedition. Fixed ropes assist climbers in scrambling over this snow covered rock band. The Yellow Band is a section of sedimentary sandstone which also requires about 100 metres of rope for traversing it.
On the South Col, climbers have entered the death zone. Climbers typically only have a maximum of two or three days they can endure at this altitude for making summit bids. Clear weather and low winds are critical factors in deciding whether to make a summit attempt. If weather does not cooperate within these short few days, climbers are forced to descend, many all the way back down to Base Camp.
From Camp IV, climbers will begin their summit push around midnight with hopes of reaching the summit (still another 1,000 metres above) within 10 to 12 hours. Climbers will first reach "The Balcony" at 8,400m (27,700 ft), a small platform where they can rest and gaze at peaks to the south and east in the early dawn light. Continuing up the ridge, climbers are then faced with a series of imposing rock steps which usually forces them to the east into waist deep snow, a serious avalanche hazard. At 8,750m (28,700 ft), a small table sized dome of ice and snow marks the South Summit.
From the South Summit, climbers follow the knife edge south east ridge along what is known as the "Cornice traverse" where snow clings to intermittent rock. This is the most exposed section of the climb as a misstep to the left would send one 2,400m (8,000 ft) down the southwest face while to the immediate right is the 3,050m (10,000 ft) Kangshung face. At the end of this traverse is an imposing 12 m (40 ft) rock wall called the "Hillary Step " at 8,760m (28,750 ft). Hillary and Tenzing were the first climbers to ascend this step and they did it with primitive ice climbing equipment and without fixed ropes. Nowadays, climbers will ascend this step using fixed ropes previously setup by Sherpas. Once above the step, it is a comparatively easy plod to the top on moderately angled snow slopes. Climbers will typically spend less than 1/2 hour on "top of the world" as they realize they need to descend to Camp IV before darkness sets in or afternoon weather becomes a serious problem.
The northeast ridge route begins from the north side of Everest in Tibet. Expeditions trek to the Rongbuk Glacier, setting up Base Camp at 5,180 m (17,000 ft) on a gravel plain just below the glacier. To reach Camp II, climbers ascend the medial moraine of the east Rongbuk Glacier up to the base of Changtse at around 6,100 m (20,000 ft). Camp III (ABC) is situated below the north col at 6,500 m (21,300 ft). To reach Camp IV on the north col, climbers ascend the glacier to the foot of the col where fixed ropes are used to reach the north col at 7,010 m (23,000 ft). From the north col, climbers ascend the rocky north ridge to setup Camp V at around 7,775 m (25,500 ft). The route goes up the north face through a series of gullies and steepens into downsloping slabby terrain before reaching the site of Camp VI at 8,230 m (27,000 ft). From Camp VI, climbers will make their final summit push. Climbers must first make their way through three rock bands known as First Step, Second Step and Third Step. Once above these steps, the final summit slopes (50 to 60 degrees) to the top.
On June 8, 1924, George Mallory and Andrew Irvine, both of the United Kingdom, made an attempt on the summit from which they never returned. Noel Odell , the expedition's geologist, saw the pair climbing up "with great alacrity... near the base of the final pyramide" [sic] at 12:50pm that day. In 1979 climber Wang Hongbao of China revealed to a companion that he had discovered a body in 1975 thought to be Irvine, but he unfortunately was killed in a fall the very next day before he could provide precise details to anyone else. In 1999 however, the famous Mallory and Irvine Research Expedition found instead Mallory's body in the predicted search area near the old Chinese camp. Controversy has raged in the mountaineering community as to whether the duo may have made it to the top of the world, 29 years before the confirmed ascent (and of course, safe descent) of Everest by Sir Edmund Hillary and Tenzing Norgay in 1953. The general consensus among climbers has been that they did not. There's no evidence of either man above the Second Step but if Mallory had made it that far then he likely summitted, for there are no difficult technical climbs further up. Almost everyone agrees Mallory died in a short fall during his descent. Irvine probably briefly survived the fall that killed Mallory, but died later of injuries and/or exposure. Irvine's body was probably found by another Chinese climber in 1960 but has not been rediscovered since, despite several searches in 2004. Mallory had gone on a speaking tour of the United States the year before in 1923; it was then that he exasperatedly gave the famous reply, "Because it is there," to a New York journalist in response to hearing the question, "Why climb Everest?" for seemingly the thousandth time. Comprehensive information is available at Mallory and Irvine: The Final Chapter including critical opposing viewpoints.
In 1995 George Mallory II of South Africa (grandson) reached the summit of Everest.
In 1933, Lady Houston , a millionaire ex-showgirl, funded the Houston Everest Flight of 1933, which saw a formation of aeroplanes led by the Marquess of Clydesdale fly over the summit in an effort to deploy the British Union Jack flag at the top.
Early expeditions ascended the mountain from Tibet, via the north face. However, this access was closed to western expeditions in 1950, after the Chinese took over Tibet. During 1951 a British led expedition, including Edmund Hillary, travelled into Nepal to survey a new route via the southern face.
Taking their cue from the British, in 1952 a Swiss expedition attempted to climb via the southern face, but the assault team of Raymond Lambert and Sherpa Tenzing Norgay turned back 200 metres short of the summit. The Swiss attempted another expedition in the autumn of 1952, this time a team including Lambert and Tenzing turned back slightly lower.
In 1953, a ninth British expedition, led by John Hunt, returned to Nepal. Hunt selected two climbing pairs to attempt to reach the summit. The first pair turned back after becoming exhausted high on the mountain. The next day, the expedition made its second and final assault on the summit with its fittest and most determined climbing pair. The summit was eventually reached at 11:30 am local time on May 29, 1953 by the New Zealander Edmund Hillary and Sherpa Tenzing Norgay from Nepal climbing the South Col Route. At the time both acknowledged it as a team effort by the whole expedition, but after interminable pestering Tenzing revealed a few years later that Hillary had put his foot on the summit first. They paused at the summit to take photographs and bury a few sweets and a small cross in the snow, before descending. News of the expedition's success reached London on the morning of Queen Elizabeth II's coronation. Returning to Kathmandu a few days later, Hillary and Hunt discovered that they had been promptly knighted for their efforts.
On May 16, 1975 Junko Tabei became the first woman to reach the summit of Everest. On May 25, 2001, Erik Weihenmayer became the first blind climber to do so.
During the 1996 climbing season, 15 people died trying to reach the summit, making it the deadliest single year in Everest history. May 10 of that year was the deadliest day in Everest history, when a storm stranded many climbers near the summit, killing eight. Among those who died were experienced climbers Rob Hall and Scott Fischer, both of whom were leading paid expeditions to the summit. Beck Weathers , a client of Hall's, survived the ordeal after being left for dead near the highest Base Camp. Journalist Jon Krakauer, on assignment from Outside magazine, was also in Hall's party, and afterwards he published the bestseller Into Thin Air which related his experience. Weathers published his story in the book Left For Dead . In May 2004, Kent Moore, a physicist from the University of Toronto, told New Scientist magazine that an analysis of weather conditions on that day suggests that freak weather caused oxygen levels to plunge by around 14%.
During the same season, climber and filmmaker David Breashears and his team filmed the IMAX feature Everest on the mountain. The 70mm IMAX camera had to be specially modified to be lightweight enough to carry up the mountain. Production was halted for several weeks so Breashears and his team could assist the survivors of the May 10 disaster, but the team eventually reached the top and filmed the first high-definition footage of the summit. On Breashears' team was Jamling Tenzing Norgay, the son of Tenzing Norgay, following in his father's footsteps for the first time.
Up to the end of the 2001 climbing season, 1491 people have reached the summit (560 of them since 1998), and there have been 172 climber deaths. The conditions on the mountain are difficult enough that most of the corpses have been left where they fell, some of them easily visible from the standard climbing routes.
Most expeditions use oxygen masks and tanks () above 26,000 feet (8,000 m); this region is known as the death zone. Everest can be climbed without supplementary oxygen, but this requires special fitness training and increases the risk to the climber: humans do not think clearly with low oxygen, and the weather, low temperatures and the slopes often require quick, accurate decisions.
Mountain climbers are a significant source of tourist revenue for Nepal; they range from experienced mountaineers to relative novices who count on their paid guides to get them to the top. The Nepalese government also requires a permit from all prospective climbers; this carries a heavy fee.
1921 The first British expedition explores the access over the Rongbuk glacier.
1922 Seven Sherpa climbers are killed in an avalanche becoming the first reported deaths on Everest.
1922 The second British expedition reaches 8321 meters.
1924 The third British expedition reaches 8500 meters. On June 6, George Mallory and Andrew Irvine ascend to attempt to reach the summit but are lost after cloud closes in. An eyewitness claims seeing them near the summit.
1933 Lady Houston funds formation of aeroplanes to fly over summit to deploy the British Union Jack flag.
1934 Maurice Wilson (British) dies on attempting to climb alone.
1950 Nepal opens its borders to foreigners.
1952 A Swiss expedition, including Sherpa Tenzing Norgay gives up from exhaustion, 200 metres short of the summit.
1953 The summit was first reached at 11:30 am on May 29 by the New Zealander Sir Edmund Hillary and Sherpa Tenzing Norgay from Nepal climbing the South Col Route.
1960 On May 25, a Chinese team makes the first summit via the North Ridge.
1963 First crossing by a United States expedition, starting from the west and descending over the south-west.
1965 On May 20, Nawang Gombu Sherpa becomes the first person to reach the summit of Everest twice.
1975 On May 16, Junko Tabei of Japan is the first woman on the crest.
- 1975 On May 27, a Tibetan woman, Phantog, becomes the first woman to reach the summit from the Tibetan side.
1978 Reinhold Messner (South Tyrol, Italy) and Peter Habeler (Austria) reach the summit without oxygen tanks .
1980 First winter expedition by a team from Poland.
- 1980 Reinhold Messner of South Tyrol, Italy, first man to climb Everest alone and without oxygen tanks .
1982 On October 5, Laurie Skreslet becomes the first Canadian to reach the summit.
1984 First Australian expedition scales Everest. Expedition comprised of Tim Macartney-Snape , Greg Mortimer, Andy Henderson and Lincoln Hall, two of which (Macartney Snape and Mortimer) made it to the summit. It is known that had Hall attempted the summit, all members would have perished on the summit.
1988 Jean-Marc Boivin of France starts with a paraglider from the mountaintop.
1990 Bertrand “Zebulon” Roche of France becomes the youngest westerner to climb Everest, age 17.
1993 90 alpinists in the autumn alone, the commercial "Everest-climbing" starts.
- 1993 Ramon Blanco of Spain became the oldest person to reach the summit aged 60 years, 160 days (record beat in 2001).
1996 Hans Kammerlander of South Tyrol, Italy climbs the mountain from the north side in 16 hours and 45 minutes and returns on skis.
- 1996 Göran Kropp of Sweden becomes first person to ride his bicycle all the way from his home in Sweden to the mountain, scale it alone without the use of oxygen tanks, and bicycle all the way back.
- 1998 Tom Whittaker is the first disabled climber to make it to the summit.
1999 Sherpa Babu Chiri Sherpa of Nepal stays for 21 hours on the mountaintop.
2001 On May 24 15-year-old Sherpa Temba Tsheri becomes the youngest person to climb Everest.
- 2001 On May 25, 32-year old Erik Weihenmayer, of Boulder, Colorado, becomes the first blind person to reach the summit.
- 2001 On the same day 64-year old Sherman Bull , of New Canaan, Connecticut, becomes the oldest person to reach the summit.
2003 On May 21, 21-year old Jess Roskelley , of Spokane, Washington, becomes the youngest American to summit Everest, via the South Col Route.
- 2003 On May 22, 23-year old Ben Clark , of Clarksville, Tennessee, becomes the second youngest American to summit Everest, via the North-Northeast Ridge Route.
- 2003 Yuichiro Miura becomes the oldest person to reach the summit of Everest. He was aged 70 years and 222 days when he got to the summit (on May 22).
- 2003 25-year-old Nepalese Sherpa, Pemba Dorjie Sherpa , makes the world's fastest ever ascent, in 12 hours 45 minutes on May 23.
- 2003 Only three days later, Sherpa Lakpa Gelu breaks this record with 10 hours 56 minutes. After a short dispute with Dorije the tourism ministry confirms Gelu's record in July. 
2004 Pemba Dorjie Sherpa smashes his own record, this time ascending the mountain in a mere 8 hours 10 minutes on May 21.