Three years after landing in a giant Martian crater, NASA's Curiosity rover has found what scientists call proof that the basin had repeatedly filled with water, bolstering chances for life on Mars. The research offered the most comprehensive picture of how Gale Crater, an ancient, 87-mile wide impact basin, formed and left a 3-mile mound of sediment standing on the crater floor. Water from north of the crater regularly filled the basin, creating long-lasting lakes that could have been a haven for life. Scientists suspect the water came from rain or snow.