If you were going to build a death star, then hide it, what would it look like? SciAm Observations today has an array of desktop backgrounds of the moon Iapetus, which orbits Saturn. Iapetus is an especially fascinating moon for many reasons. For starters, it has a giant impact crater. Also there is an equatorial ridge which encircles the entire moon, making it slightly resemble a walnut. The moon is heavily pockmarked with craters.
Image courtesy of NASA and JPL. Taken by the Cassini probe.