Evidence of seasonal flow, Mars. View panning across a false-coloured image showing stains on the Martian surface at Hale crater. Thought to be caused by the seasonal flow of water, these dark features, called recurring slope lineae, are up to hundreds of metres long. The lineae are associated with salt deposits, suggesting a briny liquid that flows during the Martian summer. The discovery of water on Mars increases the likelihood that the planet is capable of sustaining life. Image obtained by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.