There's yet more evidence of water -- and life -- on Mars coming in. Scientists got a heads up of sorts from our own Mojave Desert:
In the Mojave, the varnish was found to conceal blue-green algae that are resistant to dehydration. "The organisms in the Mojave Desert are protected from deadly ultraviolet light by the iron oxide coating," McKay said. "This survival mechanism might have played a role if Mars once had life on the surface."