At one end of the incredible Llanberis Pass, a mountain has disappeared. In its place lie immense piles of slate and a handful of enormous holes.

After nearly two centuries of of digging, slate quarrying at Dinorwic came to a halt in 1969. For every ton of slate that the Welsh unearthed, up to 30 tons went to waste, stacked so high that it became unstable and eventually made the quarries unworkable.

What remains of the quarry dominates the landscape, offering adventure to those willing to clamber the fence and explore the huts, ladders and tunnels.

Climbers have established numerous routes amongst the many sheer faces, the special properties of slate offering a unique climbing experience. Any rain turns the surfaces to glass and a showery day in April gave me opportunity to wander with my iPhone whilst waiting for routes to dry.