Deep beneath the tropical forests of the Yucatán Peninsula lies a vast subterranean domain few people can explore. Accessible by sinkholes known as âcenotesâ and potentially stretching across thousands of kilometers underground, these are the worldâs most extensive underwater cave systems. Their tunnels are dark and flooded now, but they were dry at times during the Late Pleistocene, a period approximately 126,000 to 11,700 years ago. Proof that humans and animals once roamed deep with
