In a cave in Mexico's Riviera Maya, where nature has sculpted a subterranean landscape of stunning beauty, thick steel columns supporting a controversial new tourist railway intrude into a delicate ecosystem.
The Yucatan Peninsula boasts an estimated 2,400 of these caverns and sinkholes, which are known as cenotes and are a major attraction for tourists who swim and snorkel in the crystal clear waters that fill some of them.
