View of the Dinorwic slate quarry in North Wales, UK with Llyn Peris and Llyn Padarn in the valley. At its height at the turn of the century (1900), it was the second largest slate quarry in Wales and the world - the largest was Penrhyn quarry - about 3 miles away on the other side of that mountain. Dinorwic covered 700 acres (283 ha) consisting of two main quarry sections with 20 galleries (levels) in each. Internal tramway systems connected the quarries using inclines to transport slate between galleries. Some of the old winch houses can still be seen. This is a now part of the "The Slate Landscape of Northwest Wales" which was awarded World heritage status by UNESCO in July 2021.