The eight-thousanders are 14 mountains recognised by the International Mountaineering and Climbing Federation (UIAA) with summits that exceed in elevation above sea level and are sufficiently independent of neighbouring peaks as measured by topographic prominence. There is no formally agreed-upon definition of prominence, however, and at times the UIAA has considered whether the list of 8,000-metre peaks should be expanded to 20 peaks by including the major satellite peaks of the canonical 14 eight-thousanders. All of the Earth's eight-thousanders are located in the Himalayan and Karakoram mountain ranges in Asia, and their summits lie in the altitude range known as the death zone, where atmospheric oxygen pressure is insufficient to sustain human life for extended periods of time.
From 1950 to 1964, all 14 of the eight-thousanders were first summited by expedition climbers in the summer season (the first to be summited was Annapurna I in 1950, and the last was Shishapangma in 1964); from 1980 to 2021, all 14 were summited in the winter season (the first to be summited in winter was Mount Everest in 1980, and the last was K2 in 2021). As measured by a variety of statistical techniques, the deadliest eight-thousander is Annapurna I, with one death (climber or climber support) for every three summiteers, followed by K2 and Nanga Parbat (each with one death for every four to five summiteers), and then Dhaulagiri and Kangchenjunga (each with one death for every six to seven summiteers).
The first person to summit all 14 eight-thousanders was the Italian climber Reinhold Messner in 1986, who did not use any supplementary oxygen. In 2010, Edurne Pasaban, a Basque Spanish mountaineer, became the first woman to summit all 14 eight-thousanders, though with the aid of supplementary oxygen. In 2011, Austrian Gerlinde Kaltenbrunner became the first woman to summit all 14 eight-thousanders without the aid of supplementary oxygen. In 2013, South Korean Kim Chang-ho set a speed record by climbing all 14 eight-thousanders in 7 years and 310 days, without the aid of supplementary oxygen. In July 2023, Kristin Harila and Tenjen Lama Sherpa set a speed record of 92 days for climbing all 14 eight-thousanders, with supplementary oxygen. In July 2022, Sanu Sherpa became the first person to summit all 14 eight-thousanders twice, which he did from 2006 to 2022.
The first recorded attempt on an eight-thousander was when Albert F. Mummery, Geoffrey Hastings and J. Norman Collie tried to climb Nanga Parbat in 1895. The attempt failed when Mummery and two Gurkhas, Ragobir Thapa and Goman Singh, died in an avalanche.
The first successful ascent of an eight-thousander was by the French climbers Maurice Herzog and Louis Lachenal, who reached the summit of Annapurna on 3 June 1950 using expedition climbing techniques as part of the 1950 French Annapurna expedition. Due to its location in Tibet, Shishapangma was the last eight-thousander to be ascended for the first time, which was completed by a Chinese team led by Xu Jing in 1964 (Tibet's mountains were closed by China to foreigners until 1978).
The first winter ascent of an eight-thousander was by a Polish team led by Andrzej Zawada on Mount Everest, with Leszek Cichy and Krzysztof Wielicki reaching the summit on 17 February 1980; all-Polish teams would complete nine of the first fourteen winter ascents of eight-thousanders. The final eight-thousander to be climbed in winter was K2, whose summit was ascended by a 10-person Nepalese team on 16 January 2021.
Only two climbers have completed the first ascent of more than one eight-thousander, Hermann Buhl (Nanga Parbat and Broad Peak, in 1953 and 1957) and Kurt Diemberger (Broad Peak and Dhaulagiri, in 1957 and 1960). Buhl's summit of Nanga Parbat in 1953 is notable as being the only solo first-ascent of an eight-thousander. The Polish climber Jerzy Kukuczka is noted for creating over ten new routes on various eight-thousander mountains. Italian climber Simone Moro made the first winter ascent of four eight-thousanders (Shishapangma, Makalu, Gasherbrum II, and Nanga Parbat), while three Polish climbers have each made three first winter ascents of an eight-thousander, Maciej Berbeka (Cho Oyu, Manaslu, and Broad Peak), Krzysztof Wielicki (Everest, Kangchenjunga, and Lhotse) and Jerzy Kukuczka (Dhaulagiri I, Kangchenjunga, and Annapurna I).
On 16 October 1986, Italian Reinhold Messner became the first person to climb all 14 eight-thousanders. In 1987, Polish climber Jerzy Kukuczka became the second person to accomplish this feat. Messner summited each of the 14 peaks without the aid of bottled oxygen, a feat that was only repeated by the Swiss Erhard Loretan nine years later in 1995 (Kukuczka had used supplementary oxygen while summiting Everest but on no other eight-thousander).
On 17 May 2010, Spanish climber Edurne Pasaban became the first woman to summit all 14 eight-thousanders. In August 2011, Austrian climber Gerlinde Kaltenbrunner became the first woman to climb the 14 eight-thousanders without the use of supplementary oxygen.
The first couple and team to summit all 14 eight-thousanders were the Italians Nives Meroi (who was the second woman to accomplish this feat without supplementary oxygen), and her husband on 11 May 2017. The couple climbed alpine style, without the use of supplementary oxygen or other support.
On 22 May 2024, Nepali guide Kami Rita summited Everest for the 30th time (a record for Everest), also becoming the first-ever person to climb an eight-thousander 41 times. In July 2022, Sanu Sherpa became the first person to summit all 14 eight-thousanders twice. He started with Cho Oyu in 2006, and completed the double by summiting Gasherbrum II in July 2022.
On 20 May 2013, South Korean climber Kim Chang-ho set a new speed record of climbing all 14 eight-thousanders, without the use of supplementary oxygen, in 7 years and 310 days. On 29 October 2019, the British-Nepali climber Nirmal Purja set a speed record of 6 months and 6 days for climbing all 14 eight-thousanders with the use of supplementary oxygen. On 27 July 2023, Kristin Harila and Tenjen Lama Sherpa set a new speed record of 92 days for climbing all 14 eight-thousanders with supplementary oxygen.
The eight-thousanders are some of the world's deadliest mountains. The extreme altitude and the fact that the summits of all eight-thousanders lie in the Death Zone mean that climber mortality (or death rate) is high. Two metrics are quoted to establish a death rate (i.e. broad and narrow) that are used to rank the eight-thousanders in order of deadliest.
The tables from the HDB for eight-thousanders also show that the death rate of climbers for the period 1990 to 2009 (e.g. modern expeditions), is roughly half that of the combined 1950 to 2009 period, i.e. climbing is becoming safer for the climbers attempting the summit.
From 1950 to 1964, all 14 of the eight-thousanders were summited in the summer (the first was Annapurna I in 1950, and the last was Shishapangma in 1964), and from 1980 to 2021, all 14 were summited in the winter (the first being Everest in 1980, and the last being K2 in 2021).
There is no single undisputed source or arbitrator for verified ascents of Himalayan eight-thousander peaks.
Various mountaineering journals, including the Alpine Journal and the American Alpine Journal, also maintain extensive records and archives on expeditions to the eight-thousanders, but do not always opine on disputed ascents, and nor do they maintain registers or lists of verified ascents of the eight-thousanders.
Elizabeth Hawley's The Himalayan Database, is considered as an important source for verified ascents for the Nepalese Himalayas. Online databases of Himalayan ascents pay close regard to The Himalayan Database, including the website AdventureStats.com, and the List.
The "No O<sub>2</sub>" column lists people who have climbed all 14 eight-thousanders without supplementary oxygen.
Claims have been made for summiting all 14 peaks for which not enough evidence was provided to verify the ascent; the disputed ascent in each claim is shown in parentheses in the table below. In most cases, the Himalayan chronicler Elizabeth Hawley is considered a definitive source regarding the facts of the dispute. Her The Himalayan Database is the source for other online Himalayan ascent databases (e.g. AdventureStats.com). The Eberhard Jurgalski List is also another important source for independent verification of claims to have summited all 14 eight-thousanders.
A recurrent problem with verification is the confirmation that the climber reached the true peak of the eight-thousander. Eight-thousanders present unique problems in this regard as they are so infrequently summited, their summits have not yet been exhaustively surveyed, and summiting climbers are often suffering the extreme altitude and weather effects of being in the death zone.
Cho Oyu for example, is a recurrent problem eight-thousander as its true peak is a small hump about a thirty minutes walk into the large flat summit plateau that lies in the death zone. The true peak is often obscured in very poor weather, and this led to the disputed ascent (per the table above) of British climber, Alan Hinkes (who has refused to re-climb the peak). Shishapangma is another problem peak because of its dual summits, which despite being close in height, are up to two hours climbing time apart and require the crossing of an exposed and dangerous snow ridge. When Hawley judged that Ed Viesturs had not reached the true summit of Shishapangma (which she deduced from his summit photos and interviews), he then re-climbed the mountain to definitively establish his ascent.
In a May 2021 interview with the New York Times, Jurgalski pointed out further issues with false summits on Annapurna I (a long ridge with multiple summits), Dhaulagiri (misleading false summit metal pole), and Manaslu (additional sharp and dangerous ridge to the true summit, like Shishapangma), noting that of the existing 44 accepted claims (as per the table earlier), at least 7 had serious question marks (these were in addition to the table of disputed ascents), and even noting that "It is possible that no one has ever been on the true summit of all 14 of the 8,000-meter peaks". In June 2021, Australian climber Damien Gildea wrote an article in the American Alpine Journal on the work that Jurgalski and a team of international experts were doing in this area, including publishing detailed surveys of the problem summits using data from the German Aerospace Center.
In July 2022, Jurgalski posted conclusions of the team's research (the wider team being of Rodolphe Popier and Tobias Pantel of The Himalayan Database, and Damien Gildea, Federico Bernardi, and Thaneswar Guragai). According to their analysis, only three climbers, Ed Viesturs, Veikka Gustafsson and Nirmal Purja have stood on the true summit of all 14 eight-thousanders, and no female climber had yet done so. Viesturs is also the first to have done so without the use of oxygen. Jurgalski allowed for the fact that they had deliberately not stood on the true summit of Kangchenjunga out of religious respect. The team has not formally published their work, and according to Popier, they had not decided about "the best respectful form to present it".
In 2012, to relieve capacity pressure and overcrowding on the world's highest mountain, greater restrictions were placed on expeditions to the summit of Mount Everest. To address the growing capacity constraints, Nepal lobbied the International Climbing and Mountaineering Federation (or UIAA) to reclassify five subsidiary summits (two on Lhotse and three on Kanchenjunga), as standalone eight-thousanders, while Pakistan lobbied for a sixth subsidiary summit (on Broad Peak) as a standalone eight-thousander. See table below for list of all subsidiary summits of eight-thousanders.
In 2012, the UIAA initiated the ARUGA Project, with an aim to see if these six new -plus peaks could feasibly achieve international recognition. The proposed six new eight-thousander peaks have a topographic prominence above , but none would meet the wider UIAA prominence threshold of (the lowest prominence of the existing 14 eight-thousanders is Lhotse, at ). Critics noted that of the six proposed, only Broad Peak Central, with a prominence of , would even meet the prominence threshold to be a British Isles Marilyn. The appeal noted the UIAA's 1994 reclassification of Alpine four-thousander peaks used a prominence threshold of , amongst other criteria; the logic being that if worked for summits, then is proportional for summits.
, there has been no conclusion by the UIAA and the proposals appear to have been set aside.