This stereo view of Mars' Victoria Crater combines two of the three images taken by the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter. A red-colored image was acquired with the orbiter pointed 3.84 degrees to the west and a blue-colored one with the orbiter pointed 16.2 degrees to the west.
For a 3-D view of the topography, view this image through glasses with a red filter for your left eye, and a blue or blue-green filter for your right eye. The difference in viewing angle between the two images is about 12 degrees, which is greater than the convergence angle between the left and right eyes of humans while viewing distant objects, so the vertical relief appears much steeper than is actually the case. While some of the cliffs around the crater are in fact vertical, the slopes below the cliffs are no steeper than 30 degrees.
Images from the High Resolution Imaging Science Experiment and additional information about the Mars Reconnaissance Orbiter are available online at: http://www.nasa.gov/mro.
Image credit: NASA/JPL-Caltech/University of Arizona