Israeli soldiers fire a 155mm self-propelled howitzer towards the Gaza Strip from their position along the border in the southern Israeli city of Sderot on May 20, 2021. Israel is studying whether conditions are right to stop bombing Palestinian militants in Gaza but is preparing for “more days” of strikes if necessary, an Israeli military source said today. Diplomats stepped up efforts today toward a ceasefire to stem 10 days of deadly violence between Israel and armed Palestinian groups in Gaza as air strikes again hammered targets in the enclave. (Photo by Jack Guez/AFP Photo)

A light-up bow whose arrows are advertised as flying up to 145 feet and the “Catapencil” – a pencil with a miniature slingshot-style launcher on its end – are on an annual list of unsafe toys released Wednesday by a Massachusetts-based consumer watchdog group. World Against Toys Causing Harm, or W.A.T.C.H., issued the “10 Worst Toys” list to remind parents and consumers of the potential hazards in some toys as the holiday shopping season gets underway. (Photo by Charles Krupa/AP Photo)

People wash in water from a broken water pipeline on the outskirts of Kolkata, India, March 30, 2016. (Photo by Rupak De Chowdhuri/Reuters)

A Kashmiri Muslim woman balances on a water pipe before collecting water at Dasilpora village on March 22, 2018. World Water Day is held annually on 22 March as a means of focusing attention on the importance of freshwater and advocating for the sustainable management of freshwater resources. (Photo by Tauseef Mustafa/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.

A tourist splashes water on the frozen Songhua River on December 18, 2023 in Harbin, Heilongjiang Province of China. The water immediately freezes into ice in the frigid air. (Photo by VCG/VCG via Getty Images)

A bucket of water is splashed on a woman during the Songkran water festival to celebrate the Thai New Year, in Prachinburi Province, Thailand, April 13, 2024. (Photo by Wason Wanichakorn/AP Photo)

A group of riders splash down a water slide in Bromont, Que on Monday, June 29, 2020 as water parks reopen in the province of Quebec, Canada. (Photo by Canadian Press/Rex Features/Shutterstock)