December 10, 2006
The photo above was taken inside Gusev Crater by the Mars rover "Spirit." Gusev Crater is approximately 90-miles (135 km) wide and was likely created three to four billion years ago when an asteroid plowed into Mars, just south of the Martian equator. A drainage system is visible within the crater, and it's hypothesized that liquid water, or water and ice, at one time flowed into the huge depression resulting from the impact. The two large rocks in the foreground are strongly suspected to be meteorite fragments. Over the eons, scarring or cratering by countless meteorite impacts has sculpted Mars' surface. The twin Mars rovers (Spirit and Opportunity) have now been operating for almost 1,000 days past their expected "lifetimes!"