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.

A vendor (C) serves customers at a vegetable market as a commuter train passes in Jakarta October 2, 2015. Indonesia's high annual inflation rate cooled in September and should drop more by year-end, but it likely will be 2016 before the central bank can cut interest rates to help an economy growing at its slowest pace in six years. (Photo by Reuters/Beawiharta)

Visitors wearing face masks walk near the Gwanghwamun, the main gate of the 14th-century Gyeongbok Palace, and one of South Korea's well-known landmarks, in Seoul, South Korea, Saturday, February 22, 2020. South Korea on Saturday reported a six-fold jump in viral infections in four days to 346, most of them linked to a church and a hospital in and around the fourth-largest city where schools were closed and worshipers and others told to avoid mass gatherings. (Photo by Lee Jin-man/AP Photo)

Supporters of Lebanese President Michel Aoun hold up a giant Lebanese flag as he delivers a speech outside the presidential palace in Baabda, east of Beirut, Lebanon, Sunday, October 30, 2022. Aoun left Lebanon's presidential palace Sunday marking the end of his six-year term without a replacement, leaving the small nation in a political vacuum that is likely to worsen its historic economic meltdown. (Photo by Bilal Hussein/AP Photo)

Tom Wilder, 17 from Kent, dives in the mud at the Glastonbury Festival site at Worthy Farm, Pilton on June 23, 2011 in Glastonbury, England. Music fans had to brave more rain today at the five-day festival which opened yesterday. This year the festival will feature headline acts U2, Coldplay and Beyonce. The festival, which started in 1970 when several hundred hippies paid 1 GBP to watch Marc Bolan, has grown into Europe's largest music festival attracting more than 175,000 people over five days. (Photo by Matt Cardy/Getty Images)

Tom Nevins guts a feral pig sow during hunting on Silver Plains Station on October 8, 2011 outside of Coen, Australia. Feral pigs are recognised as environmental and agricultural pests reported to have a population of up to 23.5 million over around half of Australia. The Cooktown Hog Hunt is held annually with this year's hunting window open from registration at 2pm on Friday to the end of weigh in at 2pm on Sunday afternoon. (Photo by Mark Kolbe/Getty Images)

Six-month old female liliger cub Eva plays in snow with her mother Zita in the Zoo in Novosibirsk, Russia, Thursday, December 5, 2013. The cub's mother is Zita, a liger – half-lioness, half-tiger, and its father is a lion, Sam. (Photo by Ilnar Salakhiev/AP Photo)

Two people sit in an ambulance waiting to be treated after a Grad rocket slammed into a shopping mall in Donetsk's Kubishevski district, in the eastern Ukraine, on October 8, 2014. At least two people were killed, and five were injured after some six Grad rockets hit the area. (Photo by John Macdougall/AFP Photo)