1350-6633 - Gran Cenote de Tulum in Yucatan Peninsula, Quintana Roo, Mexico. There are thousands of cenotes dotted all over Mexico���s Yucatan Peninsula, and their existence is as much a defining characteristic of the region as is the distinct geological feature from which they result. Once revered by the ancient Mayans as sacred wells, they are now magnets for tourists, adventurers, and explorers alike.