Question: What was the tallest mountain before the one where Green Boots died was discovered?

full_context: Document 1: List of past presumed highest mountains: Chimborazo, 6,267 metres (20,561 ft). Presumed highest from sixteenth century until the beginning of the 19th century. Not in the top 100 highest mountains when measured from sea level, however due to the earth's equatorial bulge this is the farthest point from the Earth's center. Nanda Devi, 7,816 metres (25,643 ft). Presumed highest in the world before Kangchenjunga was sighted in an era when Nepal was still closed to the outside world. Now known to be the 23rd highest mountain in the world. Dhaulagiri, 8,167 metres (26,795 ft). Presumed highest from 1808 until 1847. Now known to be the 7th highest mountain in the world. Kangchenjunga, 8,586 metres (28,169 ft). Presumed highest from 1847 until 1852. Now known to be the 3rd highest mountain in the world. Mount Everest, 8,848 metres (29,029 ft). Established as highest in 1852 and officially confirmed in 1856. K2, 8,611 metres (28,251 ft). Discovered in 1856 before Mt. Everest was officially confirmed, K2's elevation became something of an enigma until it was officially resolved at a later date. News media reported in 1986 that satellite measurements by the University of Washington during an expedition to K2 by George Wallenstein had given a height between 29,064 feet (8,859 m) and 29,228 feet (8,909 m). This erroneous figure was quickly retracted, and K2's status as second highest was reaffirmed.
Document 2: Olympus Mons: Olympus Mons (/ əˌlɪmpəs ˈmɒnz, oʊ -, - ˈmɒns /; Latin for Mount Olympus) is a very large shield volcano on the planet Mars. By one measure, it has a height of nearly 25 km (13.6 mi or 72,000 ft). Olympus Mons is about two and a half times Mount Everest's height above sea level. It is the largest volcano, the tallest planetary mountain, and the second tallest mountain in the Solar System compared to Rheasilvia on Vesta. It is the youngest of the large volcanoes on Mars, having formed during Mars's Hesperian Period. It had been known to astronomers since the late 19th century as the albedo feature Nix Olympica (Latin for ``Olympic Snow ''). Its mountainous nature was suspected well before space probes confirmed its identity as a mountain.
Document 3: Earth Day 20 International Peace Climb: The Earth Day 20 International Peace Climb was an expedition to reach the summit of Mount Everest during Earth Week 1990 led by Jim Whittaker, the first American to climb Mount Everest (in 1963), and marked the first time in history that mountaineers from the United States, Soviet Union and China had roped together to climb a mountain, let alone Mount Everest.
Document 4: List of longest mountain chains on Earth: Rank Range Continent Country Approx. length Approx. width Max. elevation Highest point Andes South America Argentina Bolivia Chile Colombia Ecuador Peru Venezuela 32 ° S 70 ° W ﻿ / ﻿ 32 ° S 70 ° W ﻿ / - 32; - 70 7,000 km (4,350 mi) 500 km (300 mi) 6,962 m (22,841 ft) Mount Aconcagua Southern Great Escarpment Africa Zimbabwe South Africa Swaziland Lesotho Namibia Angola 29 ° S 29 ° E ﻿ / ﻿ 29 ° S 29 ° E ﻿ / - 29; 29 5,000 km (3,100 mi) 300 km (190 mi) 3,482 m (11,424 ft) Thabana Ntlenyana Rocky Mountains North America Canada United States 39 ° N 106 ° W ﻿ / ﻿ 39 ° N 106 ° W ﻿ / 39; - 106 4,800 km (3,000 mi) 300 km (190 mi) 4,401 m (14,440 ft) Mount Elbert Transantarctic Mountains Antarctica Antarctica 84 ° S 166 ° E ﻿ / ﻿ 84 ° S 166 ° E ﻿ / - 84; 166 3,542 km (2,200 mi) 400 km (250 mi) 4,528 m (14,856 ft) Mount Kirkpatrick 5 Great Dividing Range Australia Australia 36 ° S 148 ° E ﻿ / ﻿ 36 ° S 148 ° E ﻿ / - 36; 148 3,500 km (2,175 mi) 300 km (190 mi) 2,228 m (7,310 ft) Mount Kosciuszko 6 Himalayas Asia Pakistan China Bhutan India Nepal Afghanistan Myanmar 27 ° N 86 ° E ﻿ / ﻿ 27 ° N 86 ° E ﻿ / 27; 86 2,576 km (1,600 mi) 350 km (220 mi) 8,848 m (29,029 ft) Mount Everest
Document 5: Earth: The shape of Earth is approximately oblate spheroidal. Due to rotation, the Earth is flattened along the geographic axis and bulging around the equator. The diameter of the Earth at the equator is 43 kilometres (27 mi) larger than the pole - to - pole diameter. Thus the point on the surface farthest from Earth's center of mass is the summit of the equatorial Chimborazo volcano in Ecuador. The average diameter of the reference spheroid is 12,742 kilometres (7,918 mi). Local topography deviates from this idealized spheroid, although on a global scale these deviations are small compared to Earth's radius: The maximum deviation of only 0.17% is at the Mariana Trench (10,911 metres (35,797 ft) below local sea level), whereas Mount Everest (8,848 metres (29,029 ft) above local sea level) represents a deviation of 0.14%.
Document 6: Olympus Mons: Olympus Mons (; Latin for Mount Olympus) is a very large shield volcano on the planet Mars. The volcano has a height of nearly 22 km (13.6 mi or 72,000 ft) as measured by the Mars Orbiter Laser Altimeter (MOLA). Olympus Mons is about two and a half times Mount Everest's height above sea level. It is the largest volcano, the tallest planetary mountain, and the second tallest mountain currently discovered in the Solar System, comparable to Rheasilvia on Vesta. In terms of surface area, Olympus Mons is the second-largest volcano in the solar system, second only to Earth's Tamu Massif. Olympus Mons is the youngest of the large volcanoes on Mars, having formed during Mars's Hesperian Period. It had been known to astronomers since the late 19th century as the albedo feature Nix Olympica (Latin for "Olympic Snow"). Its mountainous nature was suspected well before space probes confirmed its identity as a mountain.
Document 7: Mount Everest in 2017: The Mount Everest climbing season of 2017 began in spring with the first climbers reaching the top on May 11, from the north side. The first team on the south side reached the top on May 15. By early June, reports from Nepal indicated that 445 people had made it to the summit from the Nepali side. Reports indicate 160 -- 200 summits on the north side, with 600 -- 660 summiters overall for early 2017. This year had a roughly 50% success rate on that side for visiting climbers, which was down from other years. By 2018, the figure for the number of summiters of Everest was refined to 648. This includes 449 which summited via Nepal (from the South) and 120 from Chinese Tibet (North side).
Document 8: Mount Everest: 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. As there appeared to be several different local names, Waugh chose to name the mountain after his predecessor in the post, Sir George Everest, despite George Everest's objections.
Document 9: Tibet: Tibet has some of the world's tallest mountains, with several of them making the top ten list. Mount Everest, located on the border with Nepal, is, at 8,848 metres (29,029 ft), the highest mountain on earth. Several major rivers have their source in the Tibetan Plateau (mostly in present-day Qinghai Province). These include the Yangtze, Yellow River, Indus River, Mekong, Ganges, Salween and the Yarlung Tsangpo River (Brahmaputra River). The Yarlung Tsangpo Grand Canyon, along the Yarlung Tsangpo River, is among the deepest and longest canyons in the world.
Document 10: Ötzi: BULLET::::- Magdalena Mohar Jarc, a retired Slovenian climber, who alleged that she discovered the corpse first after falling into a crevice, and shortly after returning to a mountain hut, asked Helmut Simon to take photographs of Ötzi. She cited Reinhold Messner, who was also present in the mountain hut, as the witness to this.
Document 11: Mount Everest: 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 (8.3 in). They claimed it was the most accurate and precise measurement to date. This height is based on the highest point of rock and not the snow and ice covering it. 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.
Document 12: Green Boots: Green Boots is the name given to the unidentified corpse of a climber that became a landmark on the main Northeast ridge route of Mount Everest. Though his identity has not been officially confirmed, he is believed to be Tsewang Paljor, an Indian climber who died on Mount Everest in 1996. The term "Green Boots" originated from the green Koflach mountaineering boots that are on the feet of the corpse. All expeditions from the north side encountered the body curled in the limestone alcove cave at . In 2006, a different climber, David Sharp, died during a solo climb in what is known as "Green Boots' Cave".
Document 13: Lobsang Tshering: Lopsang Tshering Bhutia () (1951/1952–10 May 1993) was a Nepali Sherpa mountaineer who died on Mount Everest and the nephew of Tenzing Norgay. His death made international headlines because he had died on the 40th anniversary expedition of his uncle's summiting. His uncle, Tenzing Norgay, had died at home of natural causes in 1986 at the age of 72. Tenzing Norgay was the first person to summit Mount Everest in 1953 along with Sir Edmund Hillary.
Document 14: Santosh Yadav: Santosh Yadav is an Indian mountaineer. She is the first woman in the world to climb Mount Everest twice, and the first woman to successfully climb Mt. Everest from Kangshung Face. She climbed the peak first in May 1992 and then again in May 1993.
Document 15: Mount Everest: Mount Everest, known in Nepali as Sagarmatha (सगरमाथा) and in Tibetan as Chomolungma (ཇོ ་ མོ ་ གླང ་ མ), is Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The international border between Nepal (Province No. 1) and China (Tibet Autonomous Region) runs across its summit point.
ground_truth: Kangchenjunga
sub_queries: Green Boots >> place of death Answer: Mount Everest
before Mount Everest was discovered what was the tallest mountain Answer: Kangchenjunga