Mars hill find hints at wet past BBC

The US space agency’s robotic rover Spirit has found more evidence that water washed and altered the rocks it has been studying on the Red Planet.
The vehicle is examining the geology of an outcrop at Columbia Hills named Clovis, which shows chemical and physical signs of alteration by water. Sprit’s twin, Opportunity, has now completed its transect of rocks in a large crater on the other side of Mars. NASA says both rovers continue to work well as they move into Mars’ winter.