Here on our way down from the visitor center on Mauna Kea, you can see one of the many small cinder cones on its side, as well as seeing Mauna Loa across from it. Mauna Kea is 13,784 feet above sea level, and continues another 15,000 feet below sea level, for a total height of almost 29,000 feet. Mauana Loa is 13,681 feet above sea level (and still growing) and likewise goes down another 15,000 feet below sea level. If you count the base of where the mountains start Muana Kea and Mauna Loa are the first and second highest mountains on earth!