During Madrid's pride week, participants compete during the annual high heel race in Madrid, Spain, Thursday, July 29, 2023. Competitors must wear shoes with a heel of a minimum of 15 centimetres (5.9 inches). (Photo by Bernat Armangue/AP Photo)

Fire and smoke erupt from a building just after an Israeli airstrike in Beirut's southern Shayah neighbourhood on November 22, 2024, amid the ongoing war between Israel and Hezbollah. (Photo by AFP Photo/Stringer)

A performer dressed as a zombie performs inside a “Zombie Shinkansen” bullet train bound for Osaka from Tokyo, inspired by the South Korean movie “Train to Busan” ahead of the Halloween season, Japan, on October 19, 2024. (Photo by Kim Kyung-Hoon/Reuters)

Fishermen carry a tuna fish to the market in Mogadishu, Somalia, April 2, 2025. (Photo by Farah Abdi Warsameh/AP Photo)

Colombia midfielder Natalia Gaitan (3) goes up for a header against Mexico midfielder Nayeli Rangel (7) in Moncton, June 9, 2015. (Photo by Matt Kryger/USA TODAY Sports)

In this June 23, 2015 photo, Ashaninka Indian beauty contestants pose for a photo with members of a visiting music group, hired to perform during the annual founding anniversary festivities, in Otari Nativo, Pichari, Peru. The contestants wear the simple brown dresses of the Ashaninka woman, their faces dotted in a traditional design with a red dye extracted from a spice called achiote. (Photo by Rodrigo Abd/AP Photo)

A cenote is a natural phenomenon, a sinkhole in the Earth’s surface. The Yucatan Peninsula in Mexico has an estimated 7,000 cenotes because it is primarily made up of porous limestone. For millions of years, rainfall slowly ate away at the limestone and a huge system of underground caves and caverns was formed. Many filled with water from rain or from the underground water table. When the roof of a water filled cave collapses, a cenote is born. The water found in a cenote may be fresh water, salt water, or both. Structurally it may be completely open, like a lake, almost completely closed with just a small opening at the top, or somewhere in between.