Sistema Ox Bel Ha

Sistema Ox Bel Ha is a flooded underground cave system in Quintana Roo, Mexico, its name combining the Spanish "sistema" with the Yucatec Maya "ox bel ha," meaning three paths of water. First discovered in February 1996 and surveyed since by the Grupo de Exploracion Ox Bel Ha, it had been mapped to about 541.7 kilometers of passage as of February 2026, making it the longest explored underwater cave in the world, and the second-longest cave overall once dry passages are included. The system reaches a maximum depth of about 57.3 meters, is entered through roughly 160 separate cenotes across the surrounding limestone terrain, and its Naranjal subsystem has yielded three prehistoric human skeletons, including one dated to about 13,454 years ago and known as the Eve of Naharon, suggesting ritual burial practice reaching back thousands of years. This entity documents Sistema Ox Bel Ha specifically as a geological formation, the longest explored underwater cave system in the world and a major entry point into the Yucatan's flooded karst network.