Mauna Kea is a dormant volcano in the Hawaiian Islands. It is the highest point in Hawaii at 4,205 meters. If measured from top to bottom, below sea level, it is 10,200 meters high and would be the tallest mountain in the world. It is around 1,000,000 years old. Mauna Kea means 'white mountain' because in winter it often has snow at the summit. 