Cave zip-lining in Wales

Under the Snowdonia Mountains, the world’s longest underground zip-line (and deepest) was opened at Conwy Falls, North Wales, in March 2015 by Go Below Underground Adventures (Snowdonia, Wales, UK; phone +44 1690 710108, www.go-below.co.uk/default.asp).

Of three difficulty levels of treks, the easiest, “Go Below Challenge,” which takes an average of five hours, involves a short drive and hike from base camp (at the junction of the A5 and route B4406) to the mine, an underground boat ride, a zip-line, abseiling, a candle-lit lunch, a waterfall climb and an airshaft climb to the exit. The hardest trek lasts all day, “Go Below Xtreme,” with nine zip-lines over three miles of cave trekking. Trips are offered year-round and cost £39-£79 (near $60-$122).