What if you saw your shadow on Mars and it wasn't human? Then you might be the Opportunity rover currently exploring Mars. Opportunity and sister robot Spirit have been probing the red planet since early 2004, finding evidence of ancient water, and sending breathtaking images across the inner Solar System.

This view from the winter station of Mars Exploration Rover Spirit, looks across the rock strewn landscape of Gusev Crater. The dark boulders and distant hills are characteristic of the region...