Trips go deep into a disused slate mine near Blaenau Ffestiniog, using underground zip lines, abseils, traverses and boat crossings. The Challenge trip takes five hours, from age ten. The Ultimate Xtreme is a seven-hour version for adults. Deep Sleep is an overnight stay 1,375 feet underground.
Bookings are handled at the Conwy Falls office, south of Betws-y-Coed. Trips meet at the satellite base at Tanygrisiau station on the Ffestiniog Railway.