The Nili Fossae are valleys that have cut into the ancient crust of Mars, exposing clay minerals. These minerals formed in the presence of water and may be the result of chemical reactions between hot water and rocks. If so, this could have been a favorable location for Martian life in ancient times.

This HiRISE image is part of a series in search for a safe place the Mars Science Laboratory rover can land. In the central part of the image, the terrain is a mix of sand dunes and relatively smooth rock exposures. There are some small knobs but very few large rocks in the area. Instead, the multi-colored rock exposures seem to be mostly a mosaic of flat fractured rock.

On the southern edge of the image, an impact crater is a potential hazard. In the northern part of the image, the scarp marking the boundary of the valley is visible.

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.