Anti-racist Loldiers of Odin clowns speak with police as they take to the streets against anti-immigration marchers in Tampere, Finland January 23, 2016. Police prevented the groups from confronting each other. On the northern fringes of Europe, Finland has little history of welcoming large numbers of refugees, unlike neighbouring Sweden. But as with other European countries, it is now struggling with a huge increase in asylum seekers and the authorities are wary of any anti-immigrant vigilantism. (Photo by Kalle Parkkinen/Reuters/Lehtikuva)

Lebanese people take pictures for damaged grain silos in Beirut port following a huge explosion rocked the city in Beirut, Lebanon, 23 August 2020. According to Lebanese Health Ministry at least 181 people were killed, and more than 6,000 injured in the Beirut blast that devastated the port area on 04 August and believed to have been caused by an estimated 2,750 tons of ammonium nitrate stored in a warehouse. (Photo by Wael Hamzeh/EPA/EFE)

An aerial view taken on September 11, 2020 shows the Buddhist temple Wat Samphran (Dragon Temple) in Nakhon Pathom, some 40km west of Bangkok. Wat Samphran is a popular tourist destination with visitors coming to see the huge dragon figure curling around a pink cylindrical building next to the Buddha statues and places of worship of the traditional Buddhist temple complex. (Photo by Mladen Antonov/AFP Photo)

The Cage of Death at Crocosaurus Cove in Darwin City, Australia. The Cage of Death starts out above the water where the two tourists in it can see the huge crocodile below before the cage is lowered into the pen. The tourists are then inches from the 16-foot-long Saltwater crocodile as it greedily snaps its jaws over meaty treats that are being dangled right in front of the cage. (Photo by Crocosaurus Cove/Media Drum World/Profimedia)

Commuters travel in an overcrowded train near a railway station at Loni town in India's state of Uttar Pradesh on April 24, 2023. India is set to overtake China as the world's most populous country by the end of June, UN estimates showed on April 19, posing huge challenges to a nation with creaking infrastructure and insufficient jobs for millions of young people. (Photo by Arun Sankar/AFP Photo)

Three young women sprint for cover after getting caught but they were laughing with joy. Fun for some – not so much for others. Leaping over and into puddles. Torrential rain and lightning and thunder in North London Highgate on August 17, 2022. Storm drenched people out and created huge puddles for traffic People ran to escape. (Photo by Gavin Rodgers/Pixel8000)

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.