Opportunity Rover Breaks Off-World Driving Record | Video
The rover landed on the Red Planet in 2004 and has since driven a record 25.01 miles (40.02 km). The record was previously held by the Russian Lunokhod 2 which roved the lunar surface for 24.2 miles (39 km) in 1973. (Full Story)
Opportunity officially passed the 25 mile mark on July 27th, 2014.