This image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter covers a small portion of the northwest quadrant of Hellas Planitia on Mars. With a diameter of about 1,400 miles and a depth reaching the lowest elevations on Mars, Hellas is one of the largest impact craters in the solar system.
The area has a number of unusual features, which are thought to be quite old because of the high crater density. The crater inside Hellas has been filled with material, which may be related to volcanic activity on the basin's northwestern rim. It also might be related to the presence water and water ice. However, there is evidence elsewhere that the ground here is rich with ice.
HiRISE will be used to investigate this in more detail when the basin is free from atmospheric dust.
Image Credit: NASA/JPL-Caltech/University of Arizona/International Research School of Planetary Sciences