NASA has discovered a long, deep canyon and the remains of beaches which it claims is the clearest evidence yet of a widespread standing water on the surface of Mars. The large lake apparently contained liquid water when the planet was supposed to have already dried up. A warmer period must have existed when the atmosphere was thick enough to allow open water--all conditions needed to support life.
Text: http://www.reuters.com/article/scienceNews/idUSTRE55G74R20090617
