HRSC: Perspective view of Hellespontus Montes

Perspective view of Hellespontus Montes, a rocky ridge on the western rim of the vast Hellas basin in the southern hemisphere of Mars. The foreground shows a close-up of a crater with a particularly interesting feature: wrinkles that form a roughly concentric pattern, with ever-smaller arcs towards the structure’s centre. This type of feature is known as ‘concentric crater fill’, and is thought to be associated with snowfall and freezing cycles in an earlier and wetter period of Martian history… [More at link]