Hundreds of flamingos take flight in the Rift Valley in East Africa early September 2024. The birds gather in the region’s saline lakes to eat the blue-green algae that grows in abundance. The red-orange pigment in the algae is what gives them their distinctive pink plumage. They also use the site to breed. (Photo by Alexandre and Chloe Bes/Naturagency/Solent News)

Brazilian singer Larissa de Macedo Machado, better known by her stage name Anitta performs during the Coachella Valley Music and Arts Festival at the Empire Polo Club in Indio, California, U.S., April 22, 2022. (Photo by Maria Alejandra Cardona/Reuters)

Vapour bounced off the wings of the Lockheed Martin F-35 Lightning II as it sped over the Welsh mountains at a swift 575mph on February 10, 2022. The jet was taking part in a low-level training exercise through the Mach Loop – a series of valleys in North Wales. (Photo by Thomas Winstone/News Images)

Elena Ivanov, visiting from San Jose, Calif., walks across the field covered poppies in full bloom near the Antelope Valley California Poppy Reserve in Lancaster, Calif., Wednesday, March 30, 2022. (Photo by Jae C. Hong/AP Photo)

Well-wisher Nadine, holding her dog Connor wearing a knitted crown, waits for the arrival of Britain's Queen Camilla and King Charles III ahead of their visit of the Roe Valley Arts and Cultural Centre, in Limavady, Northern Ireland on March 20, 2025. (Photo by Henry Nicholls/Reuters)

Moonlight illuminates sandstone buttes in the Valley of the Gods in the proposed Bear Ears National Monument near Mexican Hat, Utah, USA, 12 November 2016. In October 2015, a coalition of five Indian nations, including the Hopi, Ute, and Navajo, formally proposed the monument, attempting to preserve the parcel's 100,000 archeological sites from ongoing looting and grave robbing. Less than two months before handing over the White House to President Elect Trump, President Obama must decide if it's worth the political capital to designate Bear Ears a national monument. (Photo by Jim Lo Scalzo/EPA)

Jaida Zuniga #5 returns a volley against Northview during a girls volleyball match on grass as part of the newly formed Grass Valley League at Northview High School in West Covina on Thursday, March 4, 2021. South Hills defeated Northview (21-25), 25-13, 25-9, 25-12. (Photo by Keith Birmingham, Pasadena Star-News/SCNG)

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.