When Mariner 10 was through with Mercury, it had taken more than 7,000 photos of the planet. Here it shows Brahms Crater, a 93-kilometer wide crater that is "typical" of Mercury. It is not known if the craters are from impacts or ancient volcanic eruptions, but it is known that rolling plains lie between the craters. When Mariner 10 ran out of power in 1975, NASA shut it down. It is believed to be orbiting the sun.