Iapetus is the third largest moon of Saturn, and eleventh-largest in the Solar System. it is an odd one due to its steep topography. Giant ice avalanches on Iapetus provide clues to similar extreme slippage elsewhere in the solar system. “We see landslides everywhere in the solar system,” says Kelsi Singer, graduate student in earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, “but Saturn’s icy moon Iapetus has more giant landslides than any body other than Mars.”