Mauna Kea is the world’s tallest mountain when measured from its oceanic base to its summit. From the seafloor to its summit, it rises about 10,205 metres, although only 4,207 metres stand above sea level.
Mauna Kea is a dormant shield volcano on Hawaii Island. Most of the volcano is submerged beneath the Pacific Ocean, so its full height is not visible from land. This measurement differs from the standard mountain-ranking method, which compares elevations above sea level and therefore places Mount Everest first.
The summit area is internationally important for astronomy because of its high altitude, dry air, and low light pollution. Mauna Kea also has deep cultural significance for Native Hawaiians. Mauna Loa is larger by volume and is another major Hawaiian volcano, but the base-to-summit height record belongs to Mauna Kea.