Tallest volcano measured from its base on the ocean floor

What to remember

Measured from sea level, Mauna Kea tops out at 4,207 m, the highest point in Hawaii. The volcano, however, starts far lower down: from its base on the ocean floor, it measures 10,203 m, or 10.203 km.

That change of starting point is what puts it ahead of Everest. Counting its submerged flanks, Mauna Kea rises higher than the Himalayan peak, and some authorities have called it the tallest mountain in the world from its underwater base. Its neighbour, Mauna Loa, is more massive but about 38 m lower.

This dormant shield volcano on the island of Hawaiʻi is nearly a million years old, the second oldest of the island's five major volcanoes, and its last eruption goes back about 4,500 years. Its height brings snow several days a year, hence the name, short for Mauna a Wākea and meaning 'White Mountain'. Traces of past glaciations have even been found on it.