Another "this should be on the news" item spotted by David:
This was only discovered in 2004, and its origin remains a mystery, though Dr Dombard (made up name?) thinks he has the answer.
What you are looking at is a 20km high icy rim on the Saturnian moon Iapetus.
Full story here:
Another of Saturn's moons, Rhea has its own weird and wonderful features, in particular: blue ice: