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.

Son doong cave is a cave in Phong Nha-Kẻ Bàng National Park, Bố Trạch district, Quảng Bình Province, Vietnam. Currently the biggest known cave in the world, the cave is located near the Laos-Vietnam border. Inside is a large, fast-flowing underground river.
In early August 2013, the first tourist group explored the cave on a guided tour at a cost of US$3,000 each. The group had six members from Australia, Norway, Russia and USA and spent 7 days and 6 nights for the tour. Next exploration trips will be arranged.

Passengers wear no trousers as they ride the London Underground in London, Britain, 07 January 2018. The No Pants Subway Ride is an global annual event where people take the public transport while they are not wearing trousers to surprise other passengers. This event takes place on the first Sunday of every year in the world's major cities. (Photo by Tolga Akmen/EPA/EFE/Rex Features/Shutterstock)

Soldiers use electronic sensors to search for missing firefighters under a line of fire trucks caught in massive gas explosions in Kaohsiung, Taiwan, Friday, August 1, 2014. A series of underground explosions about midnight Thursday and early Friday ripped through Taiwan's second-largest city, killing scores of people, Taiwan's National Fire Agency said Friday. (Photo by Wally Santana/AP Photo)

These otherworldly images give a rare glimpse inside caves barely ever seen by the human eye. With its peculiar pools of water and strange colored sediments, the bizarre looking tunnels of the Shakuranskaya cave could be a set straight out of a science fiction film. Found in the disputed region of Abkhazia, around 75 miles outside of Sochi, Russia, it is rumored the incredible underground chambers were formed after a huge earthquake struck the area in 1892. After causing part of a nearby mountain to collapse into the Amtkel River, it is thought the dam-like affect has created a series of interconnecting underground tunnels. Here: a large pool of water inside one of the tunnels. (Photo by Vladimir Mulde/Caters News)

Boys play basketball in the facilities of Belarus' Republican Clinic of Speleotherapy within a salt mine, as part of their treatment, near the town of Soligorsk, south of Minsk, February 19, 2015. According to the state clinic, more than 7,000 children and adults seek medical treatment for respiratory illness each year in the subsurface chambers of its facilities, located 420 metres underground between layers of potassium and stone salts in an operational salt mine. (Photo by Vasily Fedosenko/Reuters)

A Toyota i-Road electric vehicle drives in a underground parking lot in Tokyo April 9, 2015. Tokyoites will get a chance to zip around town on Toyota Motor Corp's three-wheeled electric car-cum-motorbike from Friday, in a trial aimed at crafting a global business model to reduce gridlock and pollution. (Photo by Thomas Peter/Reuters)

Medics help a rescued miner after an explosion and fire at a coal mine killed at least 17 miners and left up to 300 workers trapped underground, in Soma, in western Turkey, Tuesday, May 13, 2014, a Turkish official said. Twenty people were rescued from the mine but one later died in the hospital, Soma administrator Mehmet Bahattin Atci told reporters. The town is 250 kilometers (155 miles) south of Istanbul. The death toll was expected to rise. (Photo by AP Photo/Depo Photos)