Crazy cave walk in Wales

In northern Wales, near the town of Blaenau Ffestiniog, visitors can explore a man-made cavern strung with trampoline-like elastic nets.

At Bounce Below (phone +44 1248 601 444, www.bouncebelow.net), the visit begins with a 5-minute funicular journey 100 feet underground to the entrance of the cavern, which is twice the size of London’s St. Paul’s Cathedral. On foot, visitors then bounce around, navigating the cave’s trampoline-like elastic nets on a route linked by slides. Multicolored lights allow visitors to see down to the bottom of the 180-foot-deep space. A visit lasts one hour.

Guests may not weigh more than 264 pounds and must be at least seven years old to participate. Open year-round. £20 (near $32) each.