Space.com: NASA's Mars Reconnaissance Orbiter (MRO) has captured some images that suggest the debris-strewn Holden Crater once held a calm body of water. The crater debris includes a mix of broken boulders and smaller particles called megabreccia.

"Holden crater has some of the best-exposed lake deposits and ancient megabreccia known on Mars," said Alfred McEwen, principal scientist for MRO's HiRISE camera. "Both contain minerals that formed in the presence of water and mark potentially habitable environments. This would be an excellent place to send a rover or sample-return mission to make major advances in understanding if Mars supported life."