There's an insane trampoline park inside an abandoned mine in Wales

Talk about a reinvention. Formerly a Victorian Slate mine turned WWII art bunker, the 177 year-old Llechwedd Slate Caverns in Blaenau Ffestiniog, North Wales, are now a massive, subterranean playground.

Bounce Below is probably the world's largest network of trampolines, considering it features 10,000 square feet of nets. Three huge trampolines are suspended at different levels (between 20 and 180 feet above the cave's floor), and connected by slides, walkways and tunnels.

To get there, visitors will have to hop aboard an old mine train, then slide down 60 feet straight into the first trampoline. Helmets protect visitors from injury, though the whole thing - trampolines, walkways, slides and all - is basically enveloped in netting. Despite the craggy cliffs intimidating from below, walls of net make it impossible to fall off the edges.

There are three levels of trampolines: One is 20 feet above the ground floor of the cave, another 60 feet, and the highest one 180 feet. To get from one trampoline to the next, you can either take a slide (there's one in a corner of every trampoline), or bounce up and down spiral staircases.

Adding to the surreal experience are technicolored LED lights, though the calm cave vibe remains thanks to its quiet, echo-y ambiance.

This year, Bounce Below saw the addition of Junior Bounce, three trampolines meant for the younger set (ages three to six).

They already host bachelor and bachelorette parties, and even the occasional wedding, but there are also plans to build a restaurant and conference rooms for corporate events.

The old mines are also part of Zip World, and feature the world's largest underground zip line course, the longest zipline in Europe, and allegedly the fastest one in the world.