Other places on Earth that can help us understand Mars include: --Death Valley, California, where Ubehebe crater and "Mars Hill" have geologic features similar to those on Mars -- Mono Lake, California, which is a 700,000-year-old evaporative lake that compares to Gusev Crater, a basin on Mars where water once was likely -- Channeled Scabland in Washington, where catastrophic floods swept through the land much like what happened long ago in the Ares Vallis flood plain where Mars Pathfinder landed -- Permafrost in Siberia, Alaska and Antarctica, where subsurface water-ice and small life forms exist -- Volcanoes in Hawaii, which are like those on Mars, though much smaller.