Which Mountain Is the Tallest in the World?

Which mountain is the tallest in the world? That depends on how you measure them.

There are two mountains that could claim the title of the world's tallest. The summit of Mount Everest is higher above sea level than the summit of any other mountain, but Mauna Kea is the tallest when measured from base to summit.

When measuring mountain summits by their height above sea level, Mount Everest is the highest mountain in the world. Standing at 29,035 feet (8,850 meters) it reigns over the "eight-thousanders" club, a list that consists of the 14 mountains on Earth that are at least 8,000 meters tall.

Located on the border of Nepal and Tibet in the Himalayan mountain range, Mount Everest's peak was first climbed in 1953 by mountaineers Edmund Hillary and Tenzing Norgay during a British expedition.

Mauna Kea, an inactive volcano in Hawaii, is the world's tallest mountain as measured from its base, deep in the Pacific Ocean, to its summit. The discussion over what counts as Earth's tallest mountain stems from the fact that a large amount of Hawaii's Mauna Kea is underwater, and therefore measuring it from above sea level does not do justice to its massive size.

Mauna Kea's summit is at 13,796 feet (4,205 meters) above sea level, but it extends about 19,700 feet (6000 meters) below the water's surface. Therefore, its total height is 33,500 feet (10,210 meters), nearly a mile taller than Mount Everest, according to the United States Geological Survey (USGS).

Mount Kea

Mount Kea below the sea 

Mount Kea's spectacular view