Indian commuters wade through floodwaters during the continuous rain shower in Calcutta, India, July 10, 2015. A monsoon shower hit the city and disrupted daily life. The Indian monsoon, takes place between May and September. (Photo by Piyal Adhikary/EPA)

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.

Street entertainer and fortune teller “Juana La Cubana” smiles holding a cigar in her mouth as she waits for tourists in Havana, Cuba, Sunday, May 24, 2015. Juana is 72 years old and has worked in the Cathedral square in Old Havana for 28 years. (Photo by Desmond Boylan/AP Photo)

Class of 2027 plebes climb during the Herndon Monument Climb at the U.S. Naval Academy, Wednesday, May 15, 2024, in Annapolis, Md. Freshmen, known as Plebes, participate in the climb to celebrate finishing their first year at the academy. The climb was completed in two hours, nineteen minsters and eleven seconds to complete. (Photo by Tom Brenner/AP Photo)

People look out at the city among 30,375 square feet of mirrors at SUMMIT One Vanderbilt in New York on May 22, 2024. The Parade of Ships is seen from SUMMIT One Vanderbilt in NYC as part of the Fleet Week Celebration events. (Photo by Timothy A. Clary/AFP Photo)

Roman Cervenka #10 of Czechia celebrates with the trophy and gets a beer thrown on him from his teammates during IHF Ice Hockey World Championship gold medal celebrations with fans at Old Town Square on May 27, 2024 in Prague, Czech Republic. (Photo by RvS.Media/Monika Majer/Getty Images)

Ellie Alderson partner of Ollie Watkins (ENG) and Lewis Capaldi the wife of Dean Henderson (ENG) Aine May Kennedy partner of Conor Gallagher (ENG) Megan Davison wife of Jordan Pickford (ENG) at Arena Aufschalke, Gelsenkirchen, Germany on June 16, 2024. (Photo by Moritz Muller/Alamy Live News)

English model and actress Cara Delevingne poses at the Met Gala, an annual fundraising gala held for the benefit of the Metropolitan Museum of Art's Costume Institute with this year's theme “Karl Lagerfeld: A Line of Beauty”, in New York City, New York, U.S., May 1, 2023. (Photo by Andrew Kelly/Reuters)