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.

Herring worth millions in exports float dead in Kolgrafafjordur, a small fjord on the northern part of Snaefellsnes peninsula, west Iceland, for the second time in two months. Between 25,000 and 30,000 tons of fish died in December and more now, due to lack of oxygen in the fjord thought to have been caused by a landfill and bridge constructed across the fjord in December 2004. The current export value of the estimated 10,000 tons of herring amounts to $ 9.8 million, according to the newspaper “Morgunbladid”. (Photo by Brynjar Gauti/Associated Press)

Tao Xiangli gets out of his homemade submarine after operating it in a lake on the outskirts of Beijing September 3, 2009. Amateur inventor Tao, 34, made a fully functional submarine, which has a periscope, depth control tanks, electric motors, manometer, and two propellers, from old oil barrels and tools which he bought at a second-hand market. He took 2 years to invent and test the submarine which costs 30,000 yuan ($4,385). (Photo by Christina Hu/Reuters)

Adrienne Yip takes a picture of her Burmese mountain dog named “Walter”, beneath the cherry blossoms in peak bloom at the Tidal Basin with the Washington Monument seen behind, in Washington, DC, USA, 18 March 2024. Peak bloom, as defined when seventy percent of the cherry blossoms are open, is occuring this week. This year's peak bloom, beginning the 17th of March, is tied for the second earliest in history and is seen as a reflection of warming temperatures. (Photo by Michael Reynolds/EPA/EFE/Rex Features/Shutterstock)

An aerial view of a man standing on Lake Tuz, Turkiye's second largest lake, during sunset in Ankara, Turkiye on April 22, 2024. The lake, which is on the UNESCO World Heritage Tentative List with its unique natural structure, welcomes many local and foreign tourists every year as it provides 70 per cent of the country's salt needs. (Photo by Hakan Nural/Anadolu via Getty Images)

Popocatepetl volcano spews incandescent material as seen from Paso de Cortés on May 23, 2023 in Amecameca, Mexico. The second highest volcano in the country increased its activity while Mexican authorities raised the alert to yellow phase 3. Popocatepetl volcano caused the fall of ashes in different municipalities in Puebla, Estado de Mexico and Mexico City. Mexican army has spread forces as a preventive measure while the 3 levels of government are in coordination to observe the activity of the volcano and the situation in the surroundings. (Photo by Cristopher Rogel Blanquet/Getty Images)

Boca Juniors' Paraguayan defender Bruno Valdez (bottom) and Nacional's forward Bruno Damiani fight for the ball during the Copa Libertadores round of 16 second leg football match between Argentina's Boca Juniors and Uruguay's Nacional, at La Bombonera stadium in Buenos Aires, on August 9, 2023. (Photo by Juan Mabromata/AFP Photo)

“Ring Girls” attend the undercard bouts before Oleksandr Usyk of Ukraine faces Daniel Dubois of Great Britain in their undisputed heavyweight title bout at the Wembley Stadium in London, Great Britain, 19 July 2025. It is the second meeting between the WBA (Super), WBO and WBC champion Usyk and IBF title-holder Dubois following their fight in 2023 which Usyk won. (Photo by Daniel Hambury/EPA)