Timeline of Mount Everest expeditions
Mount Everest is the world's highest mountain, with a peak at 8,849 metres (29,031.7 ft) above sea level. It is situated in the Himalayan range of Solukhumbu district (Province 1 in present days), Nepal. Timeline. 1921: Reconnaissance expedition. The first British expedition—organized and financed by the newly formed Mount Everest Committee—came under the leadership of Colonel Charles Howard-Bury, with Harold Raeburn as mountaineering leader, and included George Mallory, Guy Bullock, and Edward Oliver Wheeler. It was primarily for mapping and reconnaissance to discover whether a route to the summit could be  found from the north side. As the health of Raeburn broke down, Mallory assumed responsibility for most of the exploration to the north and east of the mountain. He wrote to his wife: "We are about to walk off the map..." After five months of arduous climbing around the base of the mountain, Wheeler explored the hidden East Rongbuk Glacier and its route to the base of the North Col. On September 23, Mallory became the first person to set foot on the mountain and he, Bullock, and Wheeler reached the North Col at before being forced back by strong  winds. To Mallory's experienced eye, the route up the North ridge intersecting the NE Ridge and from there to the summit looked long, but feasible for a fresher party. 1922: First attempt. The second British expedition, under General Charles Granville Bruce and climbing leader Lt-Col. Edward Lisle Strutt, and containing Mallory, returned for a full-scale attempt on the mountain. On May 22, they climbed to 8,170 m (26,800 ft) on the North Ridge before retreating. They were the first humans to climb above on a mountain. The scope of this accomplishment is reflected by the fact that  there are only 14 mountains on earth—the eight-thousanders—that reach and exceed 8,000 metres. At that moment, Mallory and Strutt had exceeded the summit of all but five other mountains on the planet. A day later, George Finch and Geoffrey Bruce climbed up the North Ridge and Face to 8,320 m (27,300 ft) using oxygen for the first time. They climbed from the North Col to their highest camp at a phenomenal rate of 900 vert-ft/hr., and were the first climbers to sleep using oxygen. 1924: Mallory and Irvine. The third British expedition was led by  Brigadier-General Charles Bruce, although becoming indisposed as a result of a flare-up of malaria, he relinquished leadership of the expedition to Lt-Col. Edward Norton, with Mallory promoted to climbing leader. Geoffrey Bruce, Howard Somervell, and John Noel returned from the previous year, along with newcomers Noel Odell and Andrew Irvine. On June 2, Mallory and Bruce set off from the North Col (C-4) to make the first summit attempt. But extreme wind and cold, exhaustion, and the refusal of the porters to carry farther led Mallory to abandon the attempt and the next day the party returned  to the North Col camp. On June 4, Norton and Somervell attempted an oxygenless summit in perfect weather; throat trouble forced Somervell to abandon the climb at about 28,000 feet (8534 m) while Norton continued on alone, reaching a height of 8,573 m (28,126 ft), just 275 m (900 ft) short of the summit. Exhausted, he turned back and rejoined Somervell for the descent. On June 8, Mallory and Irvine left their high camp (C-6 at 26,900-ft) to attempt the summit, using Irvine's modified oxygen apparatus. Odell, climbing in support below, wrote in his diary that at 26,000 -ft he "saw Mallory & Irvine on the ridge, nearing base of final pyramid" climbing what he thought at the time was the very difficult Second Step at 12:50 p.m. It was the last time the two were seen alive; whether either of them reached the summit remains a question that has reverberated through the decades. Back in England, the climbing establishment pressured Odell to change his view. After about six months he began to equivocate on which Step it was he saw them—from the Second to possibly the First. If the First, they had no chance of having reached  the top; if the Second, they would have had about three hours of oxygen each and the summit was at least three hours away. It is conceivable (though unlikely) that Mallory might have taken Irvine's remaining oxygen and attempted to reach the summit. A much more probable scenario is that the two reached First Step at about 10:30am. Mallory, seeing the treacherous nature of the traverse to the Second Step, went it alone. He reconnoitered the base of the climbing crux and decided it was not for him that day. He returned, picked up Irvine and the two decided  to climb the First Step for a look around and to photograph the complex approach to the Second Step. It was when climbing this small promontory that they were spotted from below by Odell, who assumed that, since they were ascending, they must therefore have been on the Second Step, although it is now difficult to believe that the two would still be climbing from so low down at a time—five hours late—that was considered to be the turn-around hour. Descending from the First Step, the two continued down when, at 2pm, they were hit by  a severe snow squall. Roping up, Mallory, leading, may have slipped, pulling himself and Irvine down. The rope must have caught to inflict severe rope-jerk injury around Mallory's (and presumably, Irvine's) waist. Some researchers believe Irvine was able to stay high and struggle along the crest of the NE Ridge another 100 yards, only to succumb to cold and possible injuries of the fall. Others believe that the two became separated after the fall by the near white-out conditions of the squall. Based on his final location, it would seem that Mallory had continued straight down  in search of his partner, while Irvine, also injured, might have continued diagonally down through the Yellow Band. In 1979, climber Wang Hongbao of China revealed to the climbing leader of a Japanese expedition that in 1975, while taking a stroll from his bivouac he had discovered "an English dead" at 8100 m, roughly below the site of Irvine's ice axe discovered in 1933 near the NE Ridge. Wang was killed in an avalanche the next day before he could provide additional details. In 1999, however, Conrad Anker of the Mallory and Irvine Research Expedition found Mallory's body  in the predicted search area near the old Chinese bivouac. There are opposing views within the mountaineering community as to whether the duo may have reached the summit 29 years before the first successful ascent by Sir Edmund Hillary and Tenzing Norgay in 1953. Despite the existence of many theories, the success of Mallory and Irvine's summit assault must be viewed as remote at best. The leading theory amongst those supporting the summit push has Mallory overcoming the difficulty of the sheer face of the Second Step by standing on Irvine's shoulders. Armed with Irvine's remaining 3/4 -full oxygen tank he could conceivably have reached the summit late in the day, but this would have meant that Irvine would have had to descend by himself. However, rope-jerk injuries around Mallory's waist must mean the two were roped when they fell from below the First Step. 1960s Chinese Everest climber Xu Jing told Eric Simonson and Jochen Hemmleb in 2001 that he recalled spotting a corpse somewhere in the Yellow Band. Despite numerous searches of the north face, no sign of Irvine has turned up so far. One researcher claims to have finally spotted Irvine's  body using microscopic examination of aerial photographs. This possible discovery set off a new round of search expeditions in 2010 and 2011. 1933: Ruttledge and Houston. A major expedition, under the leadership of Hugh Ruttledge, set out to climb with the great expectations that this time they would succeed. Oxygen was taken but not used because of the incorrect but lingering belief that it was of little benefit to a properly acclimated climber. After delays caused by poor weather and illness of team members, a much higher assault camp was placed than in 1924. On the first summit attempt, Lawrence  Wager and Percy Wyn-Harris intended to follow the Northeastern ridge, but were unable to regain it, having bypassed (rather than climb over) the First Step, which they reached at 7:00am. The direct access to the Second Step from the First involves a treacherous traverse. Instead of taking it, they dropped down to follow the lower, easier traverse pioneered by Norton in 1924. Observing the Second Step from below it, Wyn-Harris declared it "unclimbable." Shortly after crossing the Great Couloir, they turned back for poor snow conditions and the lateness of the hour. A subsequent attempt by Eric Shipton  and Frank Smythe followed the same route but Smythe, who pressed on alone when Shipton turned back because of illness, got no higher. Lucy, Lady Houston, a British millionaire former showgirl, funded the Houston Everest Flight of 1933, which saw a formation of airplanes led by the Marquess of Clydesdale fly over the summit in an effort to photograph the unknown terrain. 1950. In 1950, Bill Tilman and a small party which included Charles Houston, Oscar Houston, and Betsy Cowles undertook an exploratory expedition to Everest through Nepal along the route which has now become the standard approach to Everest  from the south. 16 year old Mark Pfetzer became the youngest at the time to climb Everest. 1996. In 1996, fifteen people died trying to reach the summit, making it the deadliest year in Everest history. On May 10, a storm stranded several climbers between the summit and the safety of Camp IV, killing Rob Hall, Scott Fischer, Yasuko Namba, Doug Hansen, and guide Andy Harris on the south and the Indian (Ladakhi) climbers Tsewang Paljor, Dorje Morup, Tsewang Smanla on the north. Hall and Fischer were both highly experienced climbers who were leading paid expeditions to the summit. Journalist  Jon Krakauer, on assignment from "Outside" magazine, was in Hall's party. He published the bestseller "Into Thin Air" about the experience. Anatoli Boukreev, a guide who felt impugned by Krakauer's book, co-authored a rebuttal book called "The Climb". The dispute sparked a large debate within the climbing community. In May 2004, Kent Moore, a physicist, and John L. Semple, a surgeon, both researchers from the University of Toronto, told "New Scientist" magazine that an analysis of weather conditions on that day suggested that freak weather caused oxygen levels to plunge approximately 14%. During the same season, climber  and filmmaker David Breashears and his team filmed the IMAX feature "Everest" on the mountain (some climbing scenes were later recreated for the film in British Columbia, Canada). The 70 mm IMAX camera was specially modified to be lightweight enough to carry up the mountain, and to function in the extreme cold with the use of particular greases on the mechanical parts, plastic bearings and special batteries. Production was halted as Breashears and his team assisted the survivors of the May 10 disaster, but the team eventually reached the top on May 23 and filmed the first large format footage  of the summit. On Breashears' team was Jamling Tenzing Norgay, the son of Norgay, following in his father's footsteps for the first time. Also on his team was Ed Viesturs of Seattle, WA, who summited without the use of supplemental oxygen, and Araceli Segarra, who became the first woman from Spain to summit Everest. The storm's impact on climbers on the mountain's other side, the North Ridge, where several climbers also died, was detailed in a first hand account by British filmmaker and writer Matt Dickinson in his book "The Other Side of Everest". 2020. The Nepalese  government announced on 13 March 2020 that it was suspending all climbing permits for Mount Everest and all other peaks in the country due to concern over the effects of the COVID-19 pandemic; the Chinese government has already closed its side of Everest. On 3 April 2020 it was announced that more than two dozen Chinese climbers were tackling Mount Everest and were expected to reach the advanced base camp on Friday, although only Chinese climbers would be permitted in the spring season.