This stereo scene from NASA's Mars Exploration Rover Opportunity shows part of "Marathon Valley," a destination on the western rim of Endeavour Crater, as seen from an overlook north of the valley.

The image combines views from the left eye and right eye of Opportunity's panoramic camera (Pancam) to appear three-dimensional when seen through blue-red glasses with the red lens on the left. The component Pancam images were taken on March 13, 2015, during the 3,958th Martian day, or sol, of Opportunity's work on Mars. The scene spans from east, at left, to southeast.

The rover team selected Marathon Valley as a science destination because observations of this location using the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on NASA's Mars Reconnaissance Orbiter yielded evidence of clay minerals, a clue to ancient wet environments. By the time Opportunity explores Marathon Valley, the rover will have exceeded a total driving distance equivalent to an Olympic marathon. Opportunity has been exploring the Meridiani Planum region of Mars since January 2004.

JPL manages the Mars Exploration Rover Project for NASA's Science Mission Directorate in Washington. For more information about Spirit and Opportunity, visit http://marsrovers.jpl.nasa.gov.