This mosaic of images has been pieced together by the European Space Agency from 67 photos taken by a high-resolution stereo camera on board the Mars Expressspacecraft, currently in orbit around the Red Planet.
The system spans over one-and-a-half million square kilometres, making it one of the planet’s largest channel systems. Multiple floods are thought to have shaped Kasei Valles, triggered by volcanic activity in the nearby Tharsis region more than 3 billion years ago.
The Martian landscape was ripped apart by tectonic activity, causing immense floods as groundwater surged through the cracks. Meanwhile, heat from volcanic eruptions would have melted the surrounding snow and ice to produce torrents of dark, muddy water.
Luckily for NASA’s current Mars rovers Opportunity and Curiosity, though, there's no running water to contend with today – the planet’s average temperature is so low that any surface water is locked up as ice.