Graduates jump as they pose for photographs in front of the Tiananmen Gate and the giant portrait of late Chinese Chairman Mao Zedong, on the Tiananmen Square in Beijing, June 19, 2014. (Photo by Reuters/Stringer)

Visitors wear shirts with an image of former Chinese leader Mao Zedong at the Shanghai World Expo site in Shanghai, May 2, 2010. (Photo by Aly Song/Reuters)

The Sculpture Bank (2017) by Chinese artist Mu Boyan is exhibited along the Bondi to Tamarama Coastal walk as part of the Sculpture by the Sea exhibition in Sydney, Australia, October 18, 2018. (Photo by Charlotte Curd/The Guardian)

Children stand next to an image of a Chinese space suit displayed on a screen, at the InnoTech Expo in Hong Kong, China on December 13, 2022. (Photo by Tyrone Siu/Reuters)

Actors Rooney Mara, left, and Joaquin Phoenix arrive at the premiere of “Joker: Folie a Deux” on Monday, September 30, 2024, at TCL Chinese Theatre in Los Angeles. (Photo by Jordan Strauss/Invision/AP Photo)

Fans attend the World Premiere Of Marvel Studios' “Captain America: Brave New World” at TCL Chinese Theatre on February 11, 2025 in Hollywood, California. (Photo by Frazer Harrison/WireImage)

Royal sacred white oxen are offered food to consult the oracles during the Royal Ploughing Ceremony at the Royal Ground, Sanam Luang near the Grand Palace in Bangkok, Thailand, 09 May 2016. The ancient Brahmin rite is of great importance to the country's farmers. Thousands of farmers converge in Bangkok for the annual event, which is believed to assure a successful planting season and an abundance of crops. This year the sacred oxen ate paddy, sesame seeds, water and liquor which according to traditional soothsayers predicts that the country will have abundant food, sufficient water for agriculture as well as communication and foreign trade will improve leading to the prosperous economy. (Photo by Rungroj Yongrit/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.