Tallest ridge in the Solar System

Observations of Saturn's moon Iapetus by the NASA/ESA spacecraft Cassini-Huygens, on 31 December 2004, revealed an enormous ridge, at least 1,300 km (800 miles) long which reaches an altitude of around 20 km (12 miles) above the surface. Iapetus is 1,400 km (890 miles) across. The ridge is occasionally manifested as mountains, which rival Olympus Mons on Mars in height - the tallest mountain in the Solar System. This is more remarkable as Iapetus is five times smaller than Mars.