<http://schema.org/about>
"For four months out of every year in the ancient Mayan city of Tikal, the skies dried up and no rain fell. Nevertheless, this metropolis in what is now Guatemal"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/green-tech/research-innovations/stories/ancient-mayan-water-system-at-tikal-offers-lessons-for-today>