Look at this. It's Bounce Below, a series of enormous underground trampolines in Blaenau Ffestiniog, North Wales.
Each trampoline hangs between 20 and 180 feet above the floor in an abandoned slate mine in Blaenau Ffestiniog, North Wales.
The mine itself is twice the size of St Paul's Cathedral, and visitors have to enter it on a special train.
They climb, bounce, slide, and jump across the soft assault course in the middle of an impressive light show.