Haze-covered Titan, a moon of Saturn with a dense, cloudy atmosphere, was mapped extensively by the recent Cassini-Huygens space probe. The probe sent back beautiful space vistas like this one, whereTitan is the glowing globe behind Saturn's rings, and tiny moon Epimetheus is the small body you see floating above it. The space probe also gave up-close view of the surface of this moon, perhaps most famous for being the place where the aliens of 2001 have left a second monolith. What you may not have known is that the surface of Titan is ridged with sand dunes. Want to see them?

Above, you can see Titan's dunes. Below, there are dunes from an Earth desert. The sand formations are remarkably similar. Images via NASA.