Holy Haleakala. Emily has the goods this time: an overwhelming Iapetus mosaic, constructed by Gordan Ugarkovic:
Look at the double impact basin! I can almost imagine a binary asteroid doing that, with the right hand basin being smacked by the leading rock of the pair, followed by the other one on the left... but I can't quite convince myself. Still. Yowza.
Lousy sense of scale? To give you footing, Iapetus is about 1400 km across (900 miles), roughly the length of California. Those impact basins are freakin' huge.