In a landmark discovery, imaging scientists have seen gullies and debris flow features that suggest there could be current sources of liquid water at or near the surface of Mars. While all current Mars missions aim to understand the role of water on Mars to unlock the mystery of whether life could have developed on Mars in the past or may survive in the subsurface now or in the future, Mars Global Surveyor also has been able to characterize the topography, gravity, magnetic fields, thermal properties, surface composition, and atmosphere of Mars.