Rosie Weaver leans against the headstone of her husband, U.S. Army Spc. Michael Weaver, after a Memorial Day ceremony, Sunday, May 25, 2025, at Great Lakes National Cemetery in Holly Township, Mich. (Photo by Ayrton Breckenridge/The Flint Journal via AP Photo)

Staff from Local Ocean Conservation and fishermen lifting a mature Loggerhead sea turtle into a car, after the turtle was hooked out on the open water and needs to be taken to observation in the rehabilitation centre before being released back into the ocean, in Watamu, Kenya on May 22, 2025. (Photo by Fredrik Lerneryd/AFP Photo)

FC Barcelona's fans celebrate winning the Spanish LaLiga soccer championship at Canaletas Square in Barcelona, Spain, 15 May 2025, after the Spanish LaLiga soccer match between RCD Espanyol and FC Barcelona at the RCDE Stadium in Cornella de Llobregat. (Photo by Quique Garcia/EPA/EFE)

British-American actress Anya Taylor-Joy sticks out her tongue as she poses during a photocall for the film “Furiosa: A Mad Max Saga” at the 77th edition of the Cannes Film Festival in Cannes, southern France, on May 16, 2024. (Photo by Christophe Simon/AFP Photo)

Norwegian tennis player Jenny Stray Spetalen arrives for the screening of the film “Le Comte de Monte-Cristo” (The Count of Monte-Cristo) at the 77th edition of the Cannes Film Festival in Cannes, southern France, on May 22, 2024. (Photo by Yara Nardi/Reuters)

The first red panda cub was born on May 30 in zoo Zlin. Zoologist Roman Vrzal holds a male of red panda. The Red panda is pictured in Zlin, Czech Republic, August 20, 2014. (Photo by Dalibor Gluck/CTK)

A combination photo shows Fata Kovacevic reacting near her flood-damaged house during floods May 20, 2014 (top) and the same place after floods October 8, 2014 in Topcic Polje. (Photo by Dado Ruvic/Reuters)

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.