Cenotes are freshwater pools formed when limestone beneath the Earth’s surface dissolves or collapses exposing the water table. Invisible until some of the rock ceiling caves in, the most famous cenotes like Zaci are large: 80 meters deep (265 feet) and 45 meters (148 ft) wide. Crude numbers that don’t capture how visually surprising Cenote Zaci is at first glance at the end of its narrow staircase entrance.
Mayan communities often centered themselves physically and culturally around cenotes as these freshwater supplies were believed to be windows to the afterlife. Valuables (plus the occasional young woman) were ritualistically thrown into them to appeal or appease any number of Mayan gods. These days only tourists toss themselves gently into the chilly waters from steps leading into them; while a blogger’s cold toes recommended they instead snap photos from higher above.
Globally cenotes are usually isolated formations, but on the Yucatan Peninsula over 6,000 connect along what happens to be part of the 565 kilometer (350 miles) Chicxulub Crater‘s edge. A massive hole caused by a 10 km (6 mile) wide asteroid (or comet) which sent most dinosaurs to the reptile afterlife 66 million years ago. Cenote Zaci is a window to that world as well, watched over by dinosaur’s last living descendants we call birds, who swirl in flight at the entrance above the caves.