Titan

The Cassini spacecraft is creating a topographical map of Saturn's largest moon, Titan. Its already discovered a river basin some 250 miles long with headwaters and a delta; deserts, and vast lakes along the equatorial region. It rains on Titan as well, offering scientists proof of some type of liquid  cycle . . . the surface is made up of frozen water, the liquid cycle of frozen hydrocarbons. The ice like nature of its surface probably explains why it is relatively flat on Titan.

All very cool stuff. Read on.