<http://schema.org/about>
"Astronomers have found more evidence that Mars was wet and warm in the ancient past, but the discovery comes with a twist: The water may have flowed below the M"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/space/stories/ancient-mars-water-may-have-flowed-underground>