Mauna Kea (pronounced “mah-nah kay-ah”) is the tallest mountain in the world, 1.6 kilometers taller than Mount Everest. The main difference between Mauna Kea and Mount Everest is that Mauna Kea ascends from the ocean, instead of from land as Mount Everest does. Mauna Kea is not only the largest mountain on Earth, it is also the largest land mass in the world