J.T. Miller #9 of the Vancouver Canucks scores a goal on Alex Nedeljkovic #39 of the Pittsburgh Penguins during the second period of their NHL game at Rogers Arena on October 26, 2024 in Vancouver, British Columbia, Canada. (Photo by Derek Cain/Getty Images)

Canada's Melissa Humana-Paredes (L) and Brandie Wilkerson celebrate after defeating Argentina in the women's teams semifinals match 1 beach volleyball event during the Pan American Games Santiago 2023 at the Beach Volleyball Centre in Santiago on October 26, 2023. (Photo by Raul Arboleda/AFP Photo)

Indian Border Security Force (BSF) soldiers offer sweet to each other during the celebrations to mark country's Republic Day at the India-Pakistan Wagah border post, about 35kms from Amritsar on January 26, 2025. (Photo by Narinder Nanu/AFP Photo)

Yakut artists present a performance based on the national Yakut epic “Olonkho” on the stage of the Kyrgyz Academic Opera and Ballet Theater in Bishkek, Kyrgyzstan, 24 April 2024. The State Opera and Ballet Theater of the Republic of Sakha (Yakutia) is on tour in Bishkek on April 24 and 26. (Photo by Igor Kovalenko/EPA/EFE)

Residents wrapped in blankets watch flames engulf bamboo scaffolding at Wang Fuk Court housing estate after a major fire broke out, in Tai Po, Hong Kong, China, on November 26, 2025. (Photo by Tyrone Siu/Reuters)

British artist, Mark Coreth sits on top of the “Sydney Ice Bear” carved from a 10 tonne block of ice to illustrate how humans affect climate change in the Arctic at Customs House on June 3, 2011 in Sydney, Australia. The public will be welcomed to touch the bear, and leave an imprint which will begin the melting process and act as a metaphor for how humans affect the environment. The ice bear's has visited six cities on it's global tour since 2009; the visit to Sydney coincides with World Environment Day on June 5. (Photo by Lisa Maree Williams/Getty Images)

These photographs are the work of urban explorer Dr Bradley Garrett who made headlines back in 2012 when he posted a series of snaps from the top of The Shard skyscraper while it was still under construction. Garrett, now a researcher at the University of Oxford, took these shots during his time with the London Consolidation Crew (LCC), a loose collection of urban explorers based in the English capital. Photo: Bradley Garrett stands on the edge of the Ritz-Carlton Chicago as lightning strikes in the distance in Chicago, US. (Photo by Bradley L. Garrett/Barcroft Media)

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.