RUNNING STRAIGHT toward the horizon, Galaxias Fossae carves a line across Mars' Utopia plains. The channel formed in ground laden with ice and water when a ribbon of molten rock rose within a geologic fault. The heat triggered the escape of water, undermining the surface and creating a network of shallow channels. This view (which has no vertical exaggeration) looks west.
Photo credit: NASA/JPL/Arizona State University, R. Luk
Note: For more information, see Galaxias Fossae: The Fire Below.