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.

“Cheddar Gorge is a limestone gorge in the Mendip Hills, near the village of Cheddar in Somerset, England. The gorge is the site of the Cheddar show caves, where Britain's oldest complete human skeleton, Cheddar Man, estimated to be 9,000 years old, was found in 1903. Older remains from the Upper Late Palaeolithic era (12,000–13,000 years ago) have been found. The caves, produced by the activity of an underground river, contain stalactites and stalagmites”. – Wikipedia

Photo: A general view of Cheddar Gorge is seen on March 22, 2012 in Cheddar, England. With only a few months to go until the opening ceremony of the London 2012 Olympic games, Britain's tourist industry is hoping to benefit from the influx of athletes, officials and visitors. (Photo by Matt Cardy/Getty Images)

Mariam, a 9-year-old girl, carries her brother as she stands with other children at an underground ancient cemetery in Jabal al-Zawiya in the southern countryside of Idlib November 26, 2014. Residents are using ancient caves and cemeteries as underground shelters to hide in during shelling from forces loyal to President Bashar al-Assad. Picture taken November 26, 2014. (Photo by Khalil Ashawi/Reuters)

Wildlife photographer Danté Fenolio has headed into areas untouched by sunlight – deep seas, caves and underground – and found creatures that are exploding with colour. Here: The golden harlequin toad has vanished from the wild, and only a small number live on in captivity. A fungus caused them, and many other amphibians, to die out in their home in Central America. (Photo by Danté Fenolio/The Guardian/Johns Hopkins University Press)

Canadian-Israeli film director Simcha Jacobovici holds two nails during a press conference on April 12, 2011. Jacobovici believes that the two nails discovered in a Jerusalem cave were used in the crucifixion of Jesus Christ. Jacobovici claims that the nails were tracked to an archeology laboratory in Tel Aviv, and though cannot be 100 per cent certain that they are the nails used in the crucifixion of Jesus, he claims if “you put two and two together and they seem to imply that these are the nails”. Experts at the Israel Antiquities Authority though cast doubt on Jacobovici's claims, and suggest that nails are commonly found in such locations. (Photo by Lior Mizrahi/Getty Images)

If you are a big Batman fan with some extra frequent flier miles and cash to burn, you might want to consider staying in this amazing Batman themed hotel room! The bat cave themed hotel room goes for $50 per 3 hour stay. For that price, you not only get to stay in the coolest hotel room of all time, but you get lubrication, s*xy lingerie and other perks. Other than the price, the other downside is that you have to fly to Kaohsiung City in Taiwan to stay there. If I am ever in that part of the world, I will definitely be staying in that room, even if I am not a huge Batman fan.

If you’re afraid of heights, caves, the dark, suffer from claustrophobia or vertigo, this might not be for you, but if not, a small Welsh town has the perfect subterranean adventure for you: the world’s largest underground trampoline. Just unveiled in Blaenau Ffestiniog, North Wales, Bounce Below is a network of trampolines and slides mounted to the walls of an abandoned slate mine at heights of 20 feet to 180 feet off the ground. Visitors are welcome to climb, bounce, slide, and jump in the netting amidst a technicolor light show.

Stunning images have revealed ice-cool British tourists chilling out inside Europe’s largest glacier – despite being at risk of flooding. The spectacular collection of images show the explorers braving the freezing temperatures to climb, photograph and even abseil down the inside of the icy cliff sides. Another image shows one visitor on his knees appearing to pray next to a water fall of melted ice. Other glistening shots show an adventurer trying to keep warm by a fire whose flames dance beautifully against the glossy roof. (Photo by Einar Runar Sigurdsson/Mediadrumworld.com)