Windblown Dunes

Rippled, wind-blown sediments stretch across the Martian surface, as seen from NASA's Mars Reconnaissance Orbiter (MRO) on August 31.

Shaped by Martian weather over great periods of time, the light ripples of coarse stones crisscross dark sand dunes. Here, they can be seen filling in the upper stretch of the Valles Marineris, the Grand Canyon of Mars.