Mount Everest, 8.848 meters, 29.029 feet, Buddha Air, Nepal, Asia
Mount Everest is the Earth's highest mountain, with a peak at 8,848 metres (29,029 ft) above sea level and the 5th tallest mountain measured from the centre of the Earth. It is located in the Mahalangur section of the Himalayas. The international border between China and Nepal runs across the precise summit point. Its massif includes neighboring peaks Lhotse, 8,516 m (27,940 ft); Nuptse, 7,855 m (25,771 ft) and Changtse, 7,580 m (24,870 ft). In 1856, the Great Trigonometric Survey of British India established the first published height of Everest, then known as Peak XV, at 29,002 ft (8,840 m). In 1865, Everest was given its official English name by the Royal Geographical Society upon a recommendation by Andrew Waugh, the British Surveyor General of India. Waugh named the mountain after his predecessor in the post, Sir George Everest. Although Tibetans had called Everest "Chomolungma" for centuries, Waugh was unaware of this because Nepal and Tibet were closed to foreigners. Mount Everest attracts many highly experienced mountaineers as well as capable climbers willing to hire professional guides. While not posing substantial technical climbing challenges on the standard route, Everest presents dangers such as altitude sickness, weather and wind. The 8,848 m (29,029 ft) height given is officially recognised by Nepal and China, although Nepal is planning a new survey. On 9 October 2005, after several months of measurement and calculation, the Chinese Academy of Sciences and State Bureau of Surveying and Mapping officially announced the height of Everest as 8,844.43 m (29,017.16 ft) with accuracy of ±0.21 m (0.69 ft). They claimed it was the most accurate and precise measurement to date. This height is based on the actual highest point of rock and not on the snow and ice covering it (if one was to measure the tallest mountain on Earth from base to peak above sea level [not from the Earth's core to the peak] including snow and ice, K2 would own this title). The Chinese team also measured a snow/ice depth of 3.5 m (11 ft), which is in agreement with a net elevation of 8,848 m (29,029 ft). The snow and ice thickness varies over time, making a definitive height of the snow cap impossible to determine. In 1856, Andrew Waugh announced Everest (then known as Peak XV) as 29,002 ft (8,840 m) high, after several years of calculations based on observations made by the Great Trigonometric Survey. The elevation of 8,848 m (29,029 ft) was first determined by an Indian survey in 1955, made closer to the mountain, also using theodolites. It was subsequently reaffirmed by a 1975 Chinese measurement 8,848.13 m (29,029.30 ft). In both cases the snow cap, not the rock head, was measured. In May 1999 an American Everest Expedition, directed by Bradford Washburn, anchored a GPS unit into the highest bedrock. A rock head elevation of 8,850 m (29,035 ft), and a snow/ice elevation 1 m (3 ft) higher, were obtained via this device. Although it has not been officially recognized by Nepal, this figure is widely quoted. Geoid uncertainty casts doubt upon the accuracy claimed by both the 1999 and 2005 surveys. A detailed photogrammetric map (at a scale of 1:50,000) of the Khumbu region, including the south side of Mount Everest, was made by Erwin Schneider as part of the 1955 International Himalayan Expedition, which also attempted Lhotse. An even more detailed topographic map of the Everest area was made in the late 1980s under the direction of Bradford Washburn, using extensive aerial photography. It is thought that the plate tectonics of the area are adding to the height and moving the summit northeastwards. Two accounts suggest the rates of change are 4 mm (0.16 in) per year (upwards) and 3 to 6 mm (0.12 to 0.24 in) per year (northeastwards), but another account mentions more lateral movement (27 mm/1.1 in), and even shrinkage has been suggested. Mt. Everest has two main climbing routes, the southeast ridge from Nepal and the north ridge from Tibet, as well as many other less frequently climbed routes. Of the two main routes, the southeast ridge is technically easier and is the more frequently used route. It was the route used by Edmund Hillary and Tenzing Norgay in 1953 and the first recognized of fifteen routes to the top by 1996. This was, however, a route decision dictated more by politics than by design as the Chinese border was closed to the western world in the 1950s after the People's Republic of China invaded Tibet.