Surface Martienne photographie par la sonde MRO (Mars Reconnaissance Orbiter) - Hirise. I Heart Hellas. Located in the southern highlands of Mars, Hellas is the deepest and broadest enclosed basin on the planet. Several lines of evidence suggest Hellas may have hosted a basin-wide sea or several ice-covered lakes early in Martian history. Light-toned, repetitive, sedimentary layers, commonly found north and west of Hellas Planitia, may have formed in this ancient body of water. This stack of layers from northern Hellas Planitia has eroded into the shape of a heart. Image is 1200 m across.