How Volcanoes Work
 Image Described in Caption Olympus Mons -- This spectacular wide-angle view was obtained by the Mars Global Surveyor's (MGS) Mars Orbiter Camera (MOC). Olympus Mons is the largest volcano in the solar system. Its base is over 600 kilometers in diameter, and it rises to 26 kilometers above the Martian surface, which is three times the height of Mt. Everest. Courtesy of NASA/Marlin Space Science Systems.