Activities The Great Outdoors Facts About Mount Everest: Highest Mountain in the World Print The Great Outdoors Climbing Highest Mountains Basics Gear Skiing Snowboarding Surfing Paddling Fishing Sailing Scuba Diving & Snorkeling By Stewart Green Stewart Green Stewart M. Green is a lifelong climber from Colorado who has written more than 20 books about hiking and rock climbing. Learn about our Editorial Process Updated on 03/17/17 Read interesting facts and stories about Mount Everest, the highest mountain in the world, including its first American ascent by Jim Whittaker; the first flight over Everest in 1933; Mount Everest's geology, climate, and glaciers; and the answer to the question: Is Mount Everest really the highest mountain in the world? 01 of 06 Is Mount Everest Really the Highest Mountain on Earth? Mount Everest is the highest mountain on planet earth from sea level. Photograph copyright Feng Wei/Getty Images Is Mount Everest really the highest mountain on planet earth? It's all about your definition of what is the highest mountain. Mount Everest, measured to be 29,035 feet above sea level by a global positioning device (GPS) on the summit in 1999, is the highest mountain in the world from the baseline of sea level. Some geographers, however, consider 13,976-foot Mauna Kea on the island of Hawaii to be the highest mountain in the world since it rises an astounding 33,480 feet above the floor of the Pacific Ocean. If you take the highest mountain to be the highest point on a radial line from the center of the earth then 20,560-foot Chimborazo, a volcano that is 98 miles from the equator in Ecuador, wins hands down since its summit is 7,054 feet further from the center of the earth than Mount Everest. This is because the earth is flatter at the north and south poles and bulges wide at the equator. 02 of 06 Mount Everest Glaciers Four great glaciers continue to carve, chisel, and sculpt Mount Everest's high ridges and deep cirques. Photograph copyright Feng Wei/Getty Images Mount Everest was dissected by glaciers into a huge pyramid with three faces and three major ridges on the north, south, and west sides of the mountain. Four major glaciers continue to chisel Mount Everest: Kangshung Glacier on the east; East Rongbuk Glacier on the northeast; Rongbuk Glacier on the north; and Khumbu Glacier on the west and southwest. 03 of 06 Mount Everest Climate High winds rake the summit of Mount Everest, making it one of the most inhospitable climates on the planet. Photograph copyright Hadynyah/Getty Images Mount Everest has an extreme climate. The summit temperature never rises above freezing or 32° F (0° C). Its summit temperatures in January averages -33° F (-36° C) and can drop to -76° F (-60° C). In July, the average summit temperature is -2° F (-19° C). 04 of 06 Mount Everest Geology The sedimentary and metamorphic rock layers on Mount Everest gently tilt northward while granite basement rocks are found on Nuptse and below the mountain. Photograph courtesy Pavel Novak/Wikimedia Commons Mount Everest is primarily composed of gently dipping layers of sandstone, shale, mudstone, and limestone, some metamorphosed into marble, gneiss, and schist. The uppermost sedimentary rock layers were originally deposited at the bottom of the Tetrys Sea over 400 million years ago. Many marine fossils are found in this summit rock formation, called the Qomolangma Formation. It was laid down on a seafloor that was possibly 20,000 feet below the ocean surface. The elevation difference between where the rock was deposited on the sea floor to the summit of today's Mount Everest is almost 50,000 feet! 05 of 06 1933: First Flight Over Mount Everest The first flight over Mount Everest was by two British biplanes in 1933. In 1933 a British expedition made the first flight over the summit of Mount Everest in a couple of bi-planes modified with supercharged engines, heated clothing, and oxygen systems. The Houston-Mount Everest Flight Expedition, funded by eccentric Lady Houston, involved two planes - an experimental Westland PV3 and aWestland Wallace. The landmark flight was on April 3 after an early flight by a scout plane revealed that Everest was free of clouds although pummeled by high winds. The planes, based at Purnea, flew 160 miles northwest to the mountain where they were seized by erratic winds, which pushed the planes down, requiring them to barely climb over Mount Everest. Photographs taken above the mountain, however, were disappointing since one of the photographers passed out from hypoxia when his oxygen system failed. A second flight took place on April 19. The pilots used knowledge gained from the first one to successfully approach and fly over Everest again. David McIntyre, one of the pilots, later described the summit flight: "The menacing peak with its enormous plume whirling and streaking away to the South-East at 120 miles an hour appeared to be almost underneath us but refused to get right beneath. After what seemed an interminable time, it disappeared below the nose of the aircraft." 06 of 06 1963: First American Ascent by Jim Whittaker Jim Whittaker was the first American to stand on top of Mount Everest. Photograph courtesy REI On May 1, 1963, James "Big Jim" Whittaker from Seattle, Washington, and founder of REI, became the first American to stand on the summit of Mount Everest as part of a 19-man U.S. team led by Swiss-born climber Norman Dyhrenfurth. Whittaker and Sherpa Nawang Gombu, nephew of Tenzing Norgay, made the fourth ascent of Everest. Two parties of climbers, one with Whittaker and Nawang, and another with Dyhrenfurth and Ang Dawa, were poised above the South Col for a summit attempt. High winds, however, grounded the second team but Whittaker resolved to push upward with limited oxygen. The pair struggled in the wind, stashing an extra 13-pound oxygen bottle halfway up. They passed the South Summit, then climbed over the Hillary Step. Whittaker led up the final snow slope, running out of oxygen 50 feet below the summit. He belayed Gombu up and they struggled to the summit together. They spent 20 minutes on the summit without oxygen then began the treacherous windy descent to their extra bottles. After sucking fresh oxygen, they felt refreshed and descended to the high camp. Whittaker was so exhausted he fell asleep on his sleeping bag with his crampons still on. Afterward Jim Whittaker was feted in a Seattle parade, met President Kennedy in the Rose Garden, and was voted Man of the Year in Sports by the Seattle Post-Intelligencer. Learn facts about Mount Everest, world's highest mountain, including first American ascent; first flight over Everest; Mt. Everest geology and glaciers; and is Everest really the world's highest mountain.