Martian Salt Deposits
In this image from the Mars Reconnaissance Orbiter, deposits of chlorides can be seen. Chlorides are similar to table salt. The chloride in this image resides in the bright, polygon-shapes areas. On Earth, chloride deposits were formed in the presence of water, and these formations on Mars give credibility to the theory that the planet once contained liquid water. Liquid water on Mars would have created conditions that are suitable for the existence of life.
NASA / JPL-Caltech / University of Arizona