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.

A girl looks on next to a damaged car buried in mud in an area heavily affected by torrential rains and flash floods in the village of Kamuchiri, near Mai Mahiu, on April 29, 2024. At least 45 people died when a dam burst its banks near a town in Kenya's Rift Valley, police said on April 29, 2024, as torrential rains and floods battered the country The disaster raises the total death toll over the March-May wet season in Kenya to more than 120 as heavier than usual rainfall pounds East Africa, compounded by the El Nino weather pattern. (Photo by Luis Tato/AFP Photo)

Officers react at their graduation ceremony during Iraqi Army Day anniversary celebration in Baghdad January 6, 2015. Iraqi Defence Minister Khaled al-Obeidi said on Tuesday that the Iraqi military has started rebuilding after its near total collapse last summer but that the effort is still in its initial phase. (Photo by Ahmad Mousa/Reuters)

Gymnast Ahmad al-Sawas performs gymnastic moves near damaged buildings in the rebel-held Bustan al-Qasr neighbourhood of Aleppo, Syria March 26, 2016. As Syrian gymnast Ahmad al-Sawas watched his country fall apart, his Olympic dream collapsed too. The last national champion before the fighting began, he knew that supporting the anti-government side in the five-year-old civil war would prevent him from being selected for the Rio Games. (Photo by Abdalrhman Ismail/Reuters)

The abandoned Moulton and Kyle Funeral Home in Jacksonville, Fla., which is more than 150 years old, was left to rot, with the premises eerily strewn with open caskets, a hearse and embalming chemicals. Much like the corpses that were laid to rest, the remains of this building too are slowly decomposing and decaying. Black mold has engulfed the walls, and chipped tiles from the collapsed ceilings cover many of the floors. (Photo by Abandoned Southeast/Caters News Agency)

Balinese I Ketut Widanta or known as Lelut rides to collect fodder with his dogs sits on his motorbike in Canggu, Bali, Indonesia on November 05, 2021. Lelut becomes famous for his attractive style of carrying six of his rescued dogs with a modified motorbike while collecting food waste from restaurants. Currently, he takes care of twenty rescued dogs which some of them were dumped by the owners on the street due to the Covid-19 pandemic. Often he receives dog food donations from dog lovers since the collapse of Bali tourism affects his income. (Photo by Johannes P. Christo/Anadolu Agency via Getty Images)

Performers on boats take part in the Qintong Boat Festival at Qin Lake National Wetland Park on April 6, 2019 in Taizhou, Jiangsu Province of China. The boat festival is held around the Qingming Festival every year, and up to 10,000 participants from nearby villages and towns, with more than 500 boats, took part in the event this year. (Photo by Tang Dehong/VCG via Getty Images)

In this photograph taken on October 4, 2016, an Afghan baker prepares bread at his shop as he waits for customers in Lashkar Gah, the capital city of Helmand province. For years Helmand was the centerpiece of the Western military intervention in Afghanistan only for it to slip deeper into a quagmire of instability, with almost the entire southern province teetering on the verge of collapse. Intensified fighting has killed hundreds and forced thousands to flee to besieged capital Lashkar Gah, sparking a humanitarian crisis as the city – one of the last government- held enclaves – risks falling to the Taliban' s repeated ferocious assaults. (Photo by Wakil Kohsar/AFP Photo)