The National Slate Museum - Amgueddfa Llechi Cymru, Dinorwic Quarry, Llanberis, Wales. May 07, 2018
The largest working waterwheel in mainland Britain stands in the stone enclosure on the left of this image. The waterwheel was constructed in 1870 by the De Winton Company of Caernarfon and is 50 ft 5ins in diameter, 5 ft 3ins wide and was built around a 12in axle. It provided power for the quarry workshops until replaced by a Pelton Wheel.