April 24, 2009--New images from the European probe Mars Express show the so-called chaotic terrain of the Ariadnes Colles region on the red planet's southern highlands. Such landscapes contain an inexplicably large number of scattered rocks of varying sizes along with flat, mesa-like features.

Other known chaotic terrains on Mars are associated with the ancient presence of water. But researchers have not yet seen any evidence that Ariadnes Colles was once wet, sparking debate over whether winds or water created the unusual scenery.