"This set of images compares rocks seen by NASA's Opportunity rover and Curiosity rover at two different parts of Mars. On the left is "" Wopmay"" rock, in Endurance Crater, Meridiani Planum, as studied by the Opportunity rover. On the right are the rocks of the ""Sheepbed"" unit in Yellowknife Bay, in Gale Crater, as seen by Curiosity. Image released March 12, 2013."