Tulum
Today, Tulum is an important site for tourists visiting the state of Quintana Roo. In ancient times, however, this walled city served as a port for the city of Coba. The ruins sit atop a steep rocky cliff, and just offshore lies a cenote that probably was a source of freshwater for its original inhabitants.

Filmmaker Bob Giguere records students on expedition learning about Mayan use of astronomy and architecture from a tour guide at Tulum, Mexico.