Even if you're not enraptured by industrial museums, ignore the dull-sounding name and check this one out. At Dinorwig Quarry much of the slate was carved out of the open mountainside – leaving behind a jagged, sculptural cliff face that's fascinating if not exactly beautiful. The museum, occupying the Victorian workshops beside the lake (Llyn Padarn), features video clips, a huge working water wheel, workers' cottages (progressively furnished in period decor from 1861 to 1969, when the quarries closed) and demonstrations.
The turn-off is along the A4086 between the Electric Mountain exhibition centre and the Snowdon Mountain Railway station. The museum is part of Padarn Country Park.