Today's Image of Mars is from HiRISE and shows fretted terrain near Reull Vallis, a valley on Mars that appears to have been carved by water. Reull Vallis flows into Hellas Basin, which lies to the Northwest.
Scientists have detected features in Reull Vallis that indicate glacial activity similar to that found on Earth. They even speculate that Reull Vallis actually contains large amounts of water-ice just below the surface, which is exciting because it means future explorers (man or machine) that land in Reull Vallis may be able to use the landscape as a source of water (or fuel)!
Clicking on this image will take you to the high resolution version hosted by Wikipedia.