A policeman jumps as he tried to avoid a tear gas grenade thrown back towards police by protesters in the Mathare neighborhood of Nairobi, Kenya Wednesday, July 12, 2023. Kenyans angered by the rising cost of living were back protesting on the streets of the capital, Nairobi, on Wednesday, as they awaited a speech by a longtime opposition leader. (Photo by AP Photo/Stringer)

A City of Hollywood SWAT team member helps Alex Treacy from a search and rescue truck as she is evacuated from a flooded area on June 12, 2024, in Hollywood, Florida. As tropical moisture passes through the area, areas have become flooded due to the heavy rain. (Photo by Joe Raedle/Getty Images)

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.

Group of clowns protested in the old center of Sao Paulo, Brazil on October 24, 2016. They are against false clowns scare people. They say they are clowns good and that people who dress to scare clown clowns are false. The wave of evil clowns started in the US and has spread to many countries. (Photo by Cris Faga via ZUMA Wire)

A sеxy model poses for photos during the 2016 Guangzhou Sеx Culture Festival in Guangzhou city, south China' s Guangdong province on November 10, 2016. The festival has featured the latest developments and technologies of Adult toys and reproductive health products in the country. (Photo by Asia Wire)

Russian artist Maria Gasanova adjusts her make-up as she finishes “The Siberian Beauty” body art work from her “The Alive Painting” series before the opening ceremony of the Cultural Universiade as part of preparation for the 2019 Winter Universiade Krasnoyarsk, in the Siberian city of Krasnoyarsk, Russia, December 9, 2016. (Photo by Ilya Naymushin/Reuters)

Moldova's Victor Ciobanu in action with Georgia's Dato Chkhartishvili during the men's 60kg semi final at the World Wrestling Olympic Games Qualifier in Sofia, Bulgaria on May 8, 2021. (Photo by Stoyan Nenov/Reuters)

Members of the Texas Dancin' Divas take part in the Juneteenth Parade in Galveston, Texas, U.S., June 19, 2021. The United States marked Juneteenth for the first time as a federal holiday commemorating the end of the legal enslavement of Black Americans. (Photo by Adrees Latif/Reuters)