Little Green Men And Volcanoes
There are two things we know about Mars. There are no little green men living up there, since the average daytime temperature is a brisk -69F on a good day. But one feature that was alive at some time, is the largest known volcano in the solar system.
Olympus Mons, is truly a volcano of Olympian proportions, and then some. The main structure of the volcano rises to a summit that is 24km above the planet's surface. Ringing that is a rough circle of broken mountainous formations, that spread outwards for 550km and stick several kilometers into the air. At one point in its life, when there was heat from the volcano, it spewed out lava that fills a moat on the outer edge of the scarp. To put it in perspective, Mons is three times the height of Mount Everest, and as wide as the entire group of Hawaiian Islands. Given that Mars is only one-third the size of Earth, this means that the formation of Olympus Mons was a significant event in the planet's birth, or destruction.
Evidence from two of the oldest volcanoes on Mars, a mere 350 billion years young, indicates that in their formative stages, there was plenty of water around, as proven by the multitude of channels carved into the surface of the planet. Water, a necessity for life in any form, would have gone hand in hand with the minerals produced by the volcanic eruptions, to support whatever life forms existed at the time the surface