The Debate Over the World's Tallest Mountain.

While Mount Everest is considered the tallest mountain in the world based on its elevation above sea level, other mountains such as Mauna Kea, Denali, and Mount Chimborazo have been argued to be taller based on different definitions of "tallest." Mauna Kea is the tallest from base to peak, but its underwater base disqualifies it from the competition. Denali, with its base situated on land, is roughly 3,000 feet taller than Everest when measured from base to peak. Mount Chimborazo's peak is farther from the center of the Earth than any other mountain, but it only reaches an elevation of 20,564 feet above sea level.