An approximately natural color mosaic of Iapetus, the third-largest moon of Saturn, taken on December 31, 2004 by the Cassini orbiter at a distance of about 173,000 km. Two huge and ancient impact craters are visible as well as a mountain range running precisely along the equator. The north pole is approximately at the 1 o'clock position and is in darkness here. Named after the mythical Iapetus, the moon was discovered by the orbiter's namesake, Giovanni Domenico Cassini, in 1671.Photo credit: Cassini orbiter