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 boat, center, is surrounded by Japan Cost Guard's patrol boats after some activists descended from the boat on Uotsuri Island, one of the islands of Senkaku in Japanese and Diaoyu in Chinese, in East China Sea Wednesday, Aug. 15, 2012. Regional tensions flared on the emotional anniversary of Japan's World War II surrender as activists from China and South Korea used Wednesday's occasion to press rival territorial claims, prompting 14 arrests by Japanese authorities. The 14 people had traveled by boat from Hong Kong to the disputed islands controlled by Japan but also claimed by China and Taiwan. (Photo by Yomiuri Shimbun/Masataka Morita/AP Photo)

Meirav Stardinner receives a snake massage from Ada Barak at Barak's snake spa on September 11, 2008 in Talmei Elazar, Israel. Barack's income comes mostly from exhibiting her plants which eat everything from insects to small mammals. She discovered snakes' therapeutic value after letting people hold them after her act “Some people said that holding the snakes made them feel better, relaxed”, she says. “One old lady said it was soothing, like a cold compress”. Now she uses a combination of big snakes for deep massage and little ones for light massage, though all are non-venemous. (Photo by Uriel Sinai/Getty Images)

“Nomascus is the second most speciose genus of gibbons (family Hylobatidae). Originally this genus was a subgenus of Hylobates, and all individuals were considered one species, Hylobates concolor. Species within Nomascus are characterized by 52 chromosomes. Some species are all black, some light with a distinct black tuft of crown fur, and some by distinct, light-colored cheek patches. Nomascus is found from southern China (Yunnan) to southern Vietnam, and also on Hainan Island. One of the genus' species, Nomascus nasutus, has been deemed “the most critically endangered ape species in the world”. All of the species in this genus are endangered or critically endangered”. – Wikipedia

Photo: A newborn White-Cheeked Gibbon clings to its mother in the Nanning Zoo on April 12, 2004 in Nanning, Guangxi province, China. The White-Cheeked Gibbon's natural habitat is Southern China as well as Vietnam and Laos. They are classified as highly endangered and are on the brink of extinction due to poaching and reduction of natural rainforests. (Photo by Getty Images)

Groundsman Darren Cordingley on his way out of the maze on July 11, 2024. Gardeners have had their work cut out after spending a whopping 520 hours trimming one of the world's biggest hedge mazes. It has taken a team of 13 working eight hours a day for five days to tackle the enormous maze at the Longleat estate in Wiltshire, UK. (Photo by Max Willcock/Bournemouth News)

A ballet student from the Kibera based Project Elimu poses ahead of a public show in Kibera on August 14, 2024. Project Elimu, a community driven non profit organization, provides afterschool art, sport education programs for young people age 3 to 22. During school holidays the center holds street perfomances to encourage more students to join the dance center. Kibera is the largest slum in Nairobi, one of the largest in Africa. (Photo by Gordwin Odhiambo/AFP Photo)

Art graduate Katie Mills with her one of her “Kheeky” face flesh bottles that forms part of her “Bottoms Up” illustration design work during the media preview of the Edinburgh College of Art graduate show in Edinburgh on Friday, August 16, 2024. The exhibition features the work of more than 350 postgraduate students, and is part of the Edinburgh Art Festival, the UK's largest annual celebration of visual art. (Photo by Jane Barlow/PA Images via Getty Images)

One of two black-and-white ruffed lemur pups born at Blair Drummond Safari and Adventure Park, near Stirling, UK on Friday, May 24, 2024.The critically endangered lemur pups, both female were born on April 14 and have been named Nova, meaning “new” and Evie meaning “life”. (Photo by Andrew Milligan/PA Images via Getty Images)