Blaenau Ffestiniog

The mountains here are man-made. Blaenau Ffestiniog lies in a bowl of the Moelwynion in Eryri, North Wales, and the grey slopes tumbling down to its streets are the waste of 150 years of slate quarrying, blue-grey tips that shine when the rain stops and catch the sun like broken glass. The town roofed the world once, and now it sends you underground to bounce on it.

Welsh slate was a global commodity in the nineteenth century, and at its peak the industry here employed 17,000 men and cut almost half a million tons a year; in July 2021 the Slate Landscape of Northwest Wales became a World Heritage Site, and Ffestiniog, with its railway to Porthmadog, is one of its six areas. The caverns the quarrymen left are the attraction now: at Llechwedd a cable railway drops you five hundred feet into the mine on a guided tour, and next door trampoline nets are strung across a cavern as big as a cathedral, with zip lines, rope bridges and an underground golf course threading the tunnels. On the surface, Antur Stiniog runs downhill mountain-bike trails on the tips, Zip World's Titan lines fly across the quarry, and the Ffestiniog Railway's steam engines take the old slate route down the valley to the sea. The town itself is worth the walk: pillars of slate at the entrance, murals of Blodeuwedd and Bendigeidfran from the Mabinogi painted by a local artist across from the station, local sayings set into the pavements, and cafés and pubs that were here long before the zip lines. When the Moelwyn wears its cap, as they say of the cloud, the mountains are still there; you just go under them.