Between September 2008 and August 2011, NASA's Mars Rover Opportunity slowly crossed 13 miles of Martian plain en route to the Endeavour crater. During that approximately three year stretch, the rover took 309 images of what it saw along the way.
Even more remarkably, NASA was able to use data from Opportunity's accelerometers to generate a sound track for a video compilation of images from each drive day. NASA engineers sped up the low-frequency data 1,000 times to yield audible frequencies - essentially the vibrations of the rover while moving on the surface of Mars, according to Paolo Bellutta, a rover planner at NASA's Jet Propulsion Laboratory. "When the sound is louder, the rover was moving on bedrock. When the sound is softer, the rover was moving on sand," he said.
Opportunity and its sister rover, Spirit, landed on Mars in 2004 when they parachuted to opposite sides of Mars in search of geologic evidence that the Red Planet was once warmer and wet. Efforts to regain contact with Spirit ended earlier this year. It had been trapped in sand and unheard from for more than a year.