There is something undeniably fascinating about caves, with their sense of mystery and possibility. Rio Secreto was created by part of the Riviera Maya’s vast underground river system. Today explorers can wander and swim through portions of this underground river that runs for approximately eight miles. Visits to the portion that are open to the public help finance the preservation of the entire system. The site has recently been designated as one of Mexico’s most distinct and alluring nature reserves and the management of the site has been recognized by various environmental organizations for their exemplary stewardship of this unique site.