Tulum, located on the Yucatán Pennisula south of Cancún and west of the Riviera Maya, is believed to have been a center of commerce for the Mayans and a resort destination for Mayan royalty. The site has 60 structures, many of them in remarkably good shape considering they have been standing for 900 years. The entire city is built on a cliff above the water and is protected by large stone walls on three sides—in Mayan, Tulum means “walled city.”