Exploratour - The Surface of Mars
Olympus Mons
The largest volcano in the solar system is Olympus Mons, shown in the image to the left. Olympus Mons is a Martian shield volcano. The altitude of Olympus Mons is three times the altitude of the largest peak on Earth, Mt. Everest, and is as wide as the entire chain of Hawaiian Islands. Measurements returned by Mars Global surveyor demonstrate the unbelievable size of Olympus Mons. Olympus Mons is a very large volcano for a body the size of Mars, given the fact that Mars is three times smaller than the Earth.
The size of Olympus Mons, and some of the other volcanoes, suggests that Mars had already cooled sufficiently to form a lithosphere thick enough to support large volcanoes without allowing them to sink.