Geologists find evidence of water throughout this image of Arda Valles, a region on Mars. Drainage channels empty into a plain at left, while the large crater to the right of center shows evidence that it was filled with muddy sediments.  Cracks at the right formed when ice below the surface evaporated and the surface collapsed. Mars Express snapped the image in July 2015, and it was released in February 2016. [ESA/DLR/FU Berlin]