TRAMAMPOLINE! TRAMPOPLINE! If you don't get that joke, it's a Simpsons reference. Bad jokes aside, this looks like the best fun ever and we totally want to go.
An abandoned mining cave in Northern Wales has been turned into the world's first and, by default, largest underground trampoline room. Bounce Below opened a couple of weeks ago and is roughly twice the size of St. Paul's Cathedral in London.
In other words, it's big. Really big.
The company behind the cave have said that they're going to open a zip-line thingy pretty soon, which also sounds like the best fun ever.
Here's a BBC news broadcast taken from inside the caves.
Double-bounces. All the time.