This scene from NASA's Mars Exploration Rover Opportunity looks upward at "Knudsen Ridge" on the southern edge of "Marathon Valley" from inside the valley.
The view combines multiple images taken with the panoramic camera (Pancam) on Opportunity's mast on Oct. 29 and Oct. 30, 2015, during the 4,182nd and 4,183rd Martian days, or sols, of the rover's work on Mars. By February 2016, the rover ascended slopes of about 30 degrees onto the flank of Knudsen Ridge, headed for targets of "red zone" material to examine there.
NASA
<a rel="nofollow" class="external free" href="http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20318">http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20318</a>