From NASA's Goddard Space Flight Center Conceptual Image Lab:
NASA Video Illustrates MAVEN Mission's Investigation of a Lost Mars Nov. 13, 2013 NASA has prepared a new video to illustrate its Mars Atmosphere and Volatile Evolution (MAVEN) mission's investigation of dramatic climate change on Mars. Today, Mars is a cold and barren desert world, with no sign of life, at least on the surface. However, billions of years ago when the Red Planet was young, it appears to have had a thick atmosphere that was warm enough to support oceans of liquid water – a critical ingredient for life.