Scientists believe they found fresh proof of an ancient ocean on Mars in the form of a “bathtub ring” it left after it dried up billions of years ago.

Mars has long puzzled scientists. Dry riverbeds, mineral traces, and layered rocks hint at a wetter past. For decades, ...

Mars may have once had an ocean so vast that it covered one-third of the planet before evaporating billions of years ago and leaving behind a telltale sign: a flat band of land, outlining the former ...

A view from the "Kimberley" formation on Mars taken by NASA's Curiosity rover. One-third of the red planet might have once been covered by an ocean. - NASA/JPL-Caltech Mars may have once had an ocean ...