Sol 4379, May 19, 2016. The rover is slowly exploring the head of Marathon Valley, where the rocks show evidence (detected from orbit by CRISM) of alteration by water, which produced clay minerals. This Navcam view (click to enlarge) looks east down the valley, with the floor of Endeavour Crater and its far rim visible in the distance.
Opportunity raw images, its latest mission status, a location map. and atmospheric opacity, known as tau.