Photograph by Paul Nicklen
A snorkeling tourist floats in a cenote called Las Calaveras—“the skulls”—near Tulum. Local Maya got their drinking water here until about 30 years ago, when divers found bones. Archaeologists have recorded the remains of more than a hundred people, usually shrouded by the water’s primordial darkness.
See more pictures from the August 2013 feature story “Secrets of the Maya Otherworld.”