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.

The winners of The London’s Natural History Museum's prestigious Wildlife Photographer of the Year for 2013 have finally been unveiled. Selected from almost 43,000 entries from 96 countries, the winners offer a glimpse of the stunning array of natural beauty on our planet. Photo: Canada: “Lucky pounce”. “Anticipating the pounce – that was the hardest part”, says Connor, who had come to Yellowstone National Park, Wyoming, USA, in search of wildlife as much as the spectacular landscape. He had found this fox, his first ever, on his last day in the park. It was so absorbed in hunting that Connor had plenty of time to get out of the car and settle behind a rock. It quartered the grassland, back and forth, and then started staring intently at a patch of ground, giving Connor just enough warning of the action to come. When it sprung up, Connor got his shot. And when it landed, the fox got his mouse. (Photo by Connor Stefanison/Wildlife Photographer of the Year 2013)

Dead sperm whales are seen washed up on a beach on Texel Island, The Netherlands, January 13, 2016. The five sperm whales that beached on the Dutch lsland of Texel on Tuesday have died overnight, Dutch media reported. It is extremely unusual for so many whales to be in Dutch waters, a spokesman for the Ecomare marine centre told local paper Noordhollands Dagblad. Efforts to get the whales back into open water on Tuesday evening failed and rescuers finally withdrew from the beach at around midnight. The area of beach where the whales are has been closed to the public, to minimise the distress to the animals. (Photo by Cris Toala Olivares/Reuters)

Winti spiritual leader Ramon Mac-Nack (2nd L) looks on as as his bride Melissa Karwafodi (2nd R) hands a gourd to a Maroon priest (L) as they are wedded in the first Winti marriage ever to be held in public, in district Para, Suriname, November 16, 2015. The Winti religion, which formed centuries ago out of elements of different religious traditions that African slaves brought with them to Suriname, was considered a form idolatry and prohibited by law since the days of slavery until it was finally officially recognized in 1971. (Photo by Ranu Abhelakh/Reuters)

Krystian Herba, a Polish extreme cyclist jumps up the steps of Eureka Tower on a bicycle as he breaks a Guinness World Record at Eureka Tower on February 4, 2014 in Melbourne, Australia. Herba jumped up 2,919 steps on his bicycle in 1 hour 45 minutes without supporting himself with his hands or feet to break his own Guinness World Record. (Photo by Scott Barbour/Getty Images)

Participants wearing superhero costumes attend the World DC Comics Super Heroes event in San Martin de Valdeiglesias, near Madrid, April 18, 2015. To celebrate the anniversary of the publication of the very first Superman story, DC Comics are asking fans to help set a new world record for the largest global gathering of people dressed as DC Comics Super Heroes. (Photo by Andrea Comas/Reuters)

A visitor looks at a sculpture by a Chinese artist Chen Wenling at the "Sculpture by the Sea" exhibition which runs along the Bondi to Tamarama coastal walk in Sydney on October 22, 2015. The world's largest annual free-to-the-public outdoor sculpture exhibition runs from October 22 – November 8 this year and features over 107 sculptures by artists around the world. (Photo by Saeed Khan/AFP Photo)

National Beard and Moustache Championships 2015 Just for Men National Beard and Moustache Championships Presented by Hanes X-Temp, 2nd annual event honoring the best facial hair in America, with beardsmen from all over the world invited to compete. Categories include the Dali Moustache and the Full Beard Freestyle The World Beard and Moustache Association (WBMA) Championships have been held biennially since 1995 with the next competition due in 2017 in Kings Theatre, New York, NY, USA on November 7, 2015. (Photo by Dennis Van Tine/ABACAPress)