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.

Naomi Campbell attends the Swarovski Fashionation at Palazzo Reale on June 7, 2011 in Milan, Italy. (Photo by Vittorio Zunino Celotto/Getty Images)

“The Lovell Telescope is a radio telescope at Jodrell Bank Observatory, near Goostrey, Cheshire in the north-west of England. When it was constructed in 1955, the telescope was the largest steerable dish radio telescope in the world at 76.2 m (250 ft) in diameter; it is now the third largest, after the Green Bank telescope in West Virginia, USA, and the Effelsberg telescope in Germany. It was originally known as the 250 ft (76 m) telescope or the Radio Telescope at Jodrell Bank, before becoming the Mark I telescope around 1961 when future telescopes (the Mark II, III, and IV) were being discussed. It was renamed to the Lovell Telescope in 1987 after Bernard Lovell, and became a Grade I listed building in 1988. The telescope forms part of the MERLIN and European VLBI Network arrays of radio telescopes”. – Wikipedia

Photo: The Lovell Telescope listens to the night sky for radio signals from space at Jodrell Bank on June 22, 2011 in Holmes Chapel, England. Jodrell Bank Centre for Astrophysics and it's world famous Lovell Telescope is on the shortlist of Britain's submission for Unesco World Heritage Site status. (Photo by Christopher Furlong/Getty Images)

Mei Hoshizuki and AZM compete during the Women's Pro-Wrestling “Stardom” at Korakuen Hall on September 28, 2020 in Tokyo, Japan. (Photo by Etsuo Hara/Getty Images)

A girl looks on after a fire broke out in a slum in Dhaka, Bangladesh, March 11, 2020. (Photo by Mohammad Ponir Hossain/Reuters)

A woman walks with her daughter through an empty street on April 27, 2020 in Malaga, Spain. Since April 27 children under 12 are allowed to come and go from their homes more freely. Spain has had more than 209,000 confirmed cases of COVID-19 and over 23,000 reported deaths, although the rate has declined after weeks of lockdown measures. (Photo by Daniel Perez Garcia-Santos/Getty Images)

Commuters, some of them wearing masks as a precaution against the coronavirus ride an auto-rickshaw in Noida, outskirts of New Delhi, India, Thursday, July 16, 2020. (Photo by Altaf Qadri/AP Photo)

A laborer is transporting used oil durms by a hand-pulled vehicle near Buriganga River in Dhaka on June 12, 2021. (Photo by Md Rakibul Hasan/ZUMA Wire/Rex Features/Shutterstock)