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.

Young girls dress up in traditional costumes and pose for a selfie at the opening ceremony of the Leishan Miao new year festival in the city of Kaili, Guizhou province, China on November 23, 2015. (Photo by Imaginechina/Rex Shutterstock)

Afghan girl athletes perform Wushu on the top of a hill in Kabul, capital of Afghanistan, January 18, 2017. In the conservative Afghan society where people especially in the countryside deeply believe in the old traditions and don't allow their girls and female members of the family to go out of home, exercising sport in open is extremely risky, but a group of girls are broken the taboo and exercising Wushu on a hilltop where the temperature is minus 2 Celsius degrees. (Photo by Rahmat Alizadah/Xinhua/Barcroft Images)

A dinosaur robot produced by Tyco Electronics Japan G.K. is controlled by a smartphone at CEATEC (Combined Exhibition of Advanced Technologies) Japan 2014 held at at Makuhari Messe in Chiba, east of Tokyo, Japan, 07 October 2014.With a Sharp Aquos ZETA mobile phone model, users can make the 6.5-meter (21 feet, 4 inches) long, 2.1-meter (6 feet, 11 inches) tall dinosaur robot to walk forward and backward, jump, move its head, hands and legs up and down, left and right, open and close its mouth by touching the screen panel and make it bark by shaking the handheld. (Photo by Kimimasa Mayama/EPA)

Teacher Mahajera Armani and her class of girls pose for a picture at their study open area, founded by Bangladesh Rural Advancement Committee (BRAC), outside Jalalabad city, Afghanistan September 19, 2015. (Photo by Reuters/Parwiz)

Derby's Byron MacLean, left, edges out Hall's Joe Nham in the boys 55-meter hurdles at the CIAC State Open indoor track championships at the Floyd Little Athletic Center in New Haven, Saturday, February 17, 2024. Lyman Hall's Owen Rich, right, falls after taking down the final hurdle. (Photo by Cloe Poisson/Hartford Courant via AP Photo)

This adorable gallery reveals the astonished expressions of dozens of puppies as they try to gobble up treats flying through the air toward them. Photographer Christian Vieler, 48, has been documenting pooches, with their eyes bulging, mouths wide open and looks of love on their faces, in his studio as part of the project “Dogs Catching Treats” since 2013. (Photo by Christian Vieler/Caters News Agency)

A little girl stands next to a painted buffalo during the “Buffalo Painting” contest that is part of the Tich Dien festival in Ha Nam province, Vietnam, 10 February 2019. Artists from all over the country have gathered for the festival which attracts thousand of residents and visitors. Tich Dien festival features the importance of agriculture and the role of farmers in the vietnamese society and contributes to preserving the local cultural values. (Photo by Luong Thai Linh/EPA/EFE)