Daisy Lowe attends The Phillips British Academy Awards 2011 at The Grosvenor House Hotel on May 22, 2011 in London, England. (Photo by Dave Hogan/Getty Images)

Children, wearing traditional Bavarian folk costumes specific to their region, prepare for the competition in the “Schuhplattler” style of Bavarian folk dancing for the Bavarian Lion Award at the Huosigau Heimat and Folklore Society on May 28, 2011 in Weilheim, Germany. (Photo by Johannes Simon/Getty Images)

Indonesian activists covered with sludge from the mud volcano hold a protest during five year anniversary of the Sidoarjo mud eruption on May 29, 2011 in the subdistrict of Porong in Sidoarjo, East Java, Indonesia. (Photo by Ulet Ifansasti/Getty Images)

Interior designer Tony Alleyne stands in his «Star Trek» theme studio apartment May 16, 2003 in Hinckley, Leicestershire, England. The apartment took nearly 10 years to redesign in the style of the «Star Trek» Starship Enterprise on approximately US$1.7 million. (Photo by Ross Kinnaird/Getty Images)

Four year old Kaleb Stanley (R), from Dublin, reaches up to puncture a giant bubble with the help of his seven year old brother Jacob on London's South Bank on May 9, 2008 in England. (Photo by Peter Macdiarmid/Getty Images)

Syrian President Bashar Al Assad watches as Pope John Paul II boards his plane at Damascus airport May 8, 2001 at the end of the Pontiff's four-day visit to Syria.

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)

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.