Ice swimmer Klaudia prepares to swim in a filled up water kettle in an ice cave inside the Nature Ice Palace, with a hight of 3,250 meters (10,663 feet) above sea level, at Hintertux Glacier near Hintertux, some 480 kilometers (298 miles) western of Vienna, Austria, 28 July 2018. (Photo by Christian Bruna/EPA/EFE)

Francisca Gomez stands at an entrance to her home, a cave where she has been living for the past 50 years, in the mountains on the outskirts of Chusmuy, Honduras April 21, 2015. The 75-year old widow receives help from neighbors and friends and she makes a little money by selling wood she collects, according to a local newspaper. (Photo by Jorge Cabrera/Reuters)

Protestor Bill Maloney (L) shouts during a live TV broadcast by BBC News Channel chief political correspondent Norman Smith after earlier forcing Deputy Prime Minister Nick Clegg to abandon a photocall near Parliament on March 19, 2014 in London, England. The Chancellor of the Exchequer, George Osborne has delivered his Budget statement to Members of Parliament in the House of Commons. (Photo by Peter Macdiarmid/Getty Images)

A hillside erupts in flame as a raging wildfire fire burns in Placerita Canyon in Santa Clarita, Calif., Monday, July 25, 2016. A raging wildfire that forced thousands from their homes on the edge of Los Angeles continued to burn out of control Monday as frustrated fire officials said residents reluctant to heed evacuation orders made conditions more dangerous and destructive for their neighbors. (Photo by Nick Ut/AP Photo)

Comedian Chevy Chase gets a kiss on his ear from co-star Benji as the two held a press conference in Los Angeles, September 6, 1979, at which they announced their up-coming movie “Oh Heavenly Dog” would begin filming this month. The film will be shot on location in London, Berlin and Paris; but due to British quarantine laws a double will be used for Benji at the London location. (Photo by Nick Ut/AP Photo)

Wags the dog wears a button featuring a photo of the moment after the attempted assassination on former president Donald Trump outside the Fiserv Forum during the third day of the 2024 Republican National Convention in Milwaukee, Wisconsin, on July 17, 2024. Days after he survived an assassination attempt Donald Trump won formal nomination as the Republican presidential candidate and picked Ohio US Senator J.D. Vance for running mate. (Photo by Nick Oxford/AFP Photo)

Jacob's Well is a perennial karstic spring in the Texas Hill Country flowing from the bed of Cypress Creek, located northwest of Wimberley, Texas. The twelve foot (four meter) diameter mouth of the spring serves as a popular swimming spot for the local land owners whose properties adjoin Cypress Creek. From the opening in the creek bed, Jacob's Well cave descends vertically for about thirty feet (ten meters), then continues downward at an angle through a series of silted chambers separated by narrow restrictions, finally reaching a depth of one hundred and twenty feet (forty meters). Until the modern era, the Trinity Aquifer-fed natural artesian spring gushed water from the mouth of the cave, with a measured flow in 1924 of one hundred and seventy gallons per second (six hundred and forty liters per second) discharging six feet (two meters) into the air. The spring is the greatest source of water recharging the Edwards Aquifer.

In this photo taken on Saturday, April 22, 2017, a drawing “King for a day” is made on the back of a muddy truck by artist Nikita Golubev in Moscow, Russia. The grimy trucks traversing the polluted and dusty streets of Moscow have inspired Golubev to use white vans and trucks as his canvas to create this ephemeral street art and signs his drawings Pro Boy Nick. (Photo by Pavel Golovkin/AP Photo)