First Hard Evidence Discovered of a Lake on Mars

A research team discovered definitive evidence of shorelines on Mars from a three billion year old lake. The lake at its peak was up to 80 square miles and 1,500 feet deep. A shoreline is evidence of liquid, possibly water. Water may mean life. The shoreline may make a great target for a probe.

http://www.eurekalert.org/pub_releases/2009-06/uoca-uoc061709.php

"A University of Colorado at Boulder research team has discovered the first definitive evidence of shorelines on Mars, an indication of a deep, ancient lake there and a finding with implications for the discovery of past life on the Red Planet.

Estimated to be more than 3 billion years old, the lake appears to have covered as much as 80 square miles and was up to 1,500 feet deep -- roughly the equivalent of Lake Champlain bordering the United States and Canada, said CU-Boulder Research Associate Gaetano Di Achille, who led the study. The shoreline evidence, found along a broad delta, included a series of alternating ridges and troughs thought to be surviving remnants of beach deposits."