... What does the surface of Saturn's mysterious moon Iapetus look like? To help find out, the robotic Cassini spacecraft now orbiting Saturn was sent soaring last week just 2,000 kilometers from the unique equatorial ridge of the unusual walnut-shaped two-toned moon. ... Inside Victoria Crater on Mars . ... Iapetus: 3D Equatorial Ridge . ... This bizarre, equatorial ridge extending across and beyond the dark, leading hemisphere of Iapetus gives the two-toned Saturnian moon a distinct walnut shape. ...