Nasa space pictures
This non-circular pit is due to a low angle impact from an asteroid or comet. The raised plateau west of the crater was where most of the impact debris landed. This debris protected the material underneath, but else where this material was slowly removed by the wind and the debris-covered area was left behind as this high-standing and interestingly-shaped Martian plateau. Image: NASA/JPL/University of Arizona [high-resolution] Caption: HiRISE Science Team
The High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter often takes images of Martian sand dunes to study the mobile soils. These images provide information about erosion and movement of surface material, about wind and weather patterns, even about the soil grains and grain sizes.
The Syrtis Major Volcanic Province. Acquired by the High Resolution Stereo Camera on ESA’s Mars Express Satellite, this image depicts a detailed region of the Martian Nili Fossae Graben system. This system is an area of great interest to geologists due to the variety of its landscape. The graben system contains numerous troughs, plateaus, impact craters and depressions.