This series of images shows warm-season features that might be evidence of salty liquid water active on Mars today.
Evidence for that possible interpretation is presented in a report by McEwen et al. in the Aug. 5, 2011, edition of Science.
These images come from observations of Newton crater, at 41.6 degrees south latitude, 202.3 degrees east longitude, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. In time, the series spans from early spring of one Mars year to mid-summer of the following year. The images have been adjusted to correct those taken from oblique angles to show how the scene would look from directly overhead.
Source by Nasa