Women pose for a selfie at Ipanema Beach in Rio de Janeiro, Brazil on July 30, 2016. (Photo by Nacho Doce/Reuters)

Russian fashion model Irina Shayk bares it all while getting ready for the Rio Carnival parade in Brazil early March 2025. (Photo by irinashayk/Instagram)

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.

Syrian Tulin Hashemi waits for a job interview at a hotel in Vidigal slum in Rio de Janeiro, Brazil, September 22, 2015. Tulin, whose mother arrived two days ago, has been living in Brazil for two months. As she does not speak Portuguese, Tulin says it is difficult for her to find a job and therefore she is staying at the slum as it is one of the cheaper neighbourhoods to live in. According to the National Committee for Refugees (CONARE), 2,077 people fleeing the Syrian civil war have settled in Brazil, whilst a quarter of the 8,400 refugees in the Latin American country come from Syria. (Photo by Pilar Olivares/Reuters)

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)

People participate in a Zombie Walk in Sao Paulo, Brazil, November 2, 2016. (Photo by Nacho Doce/Reuters)

A visitor poses for a picture during Sao Paulo Fashion Week in Sao Paulo, Brazil, March 16, 2017. (Photo by Nacho Doce/Reuters)