Coal mining played a central role in the development of this part of Nova Scotia, so you shouldn't pass up the chance to venture into a disused mine in the company of a former miner. It's fascinating, a little spooky, and not for the claustrophobic. The museum has interesting exhibits on this aspect of Cape Breton's past. It's at Glace Bay, 22km east of Sydney.
There's also a restaurant, and in summer the Men of the Deeps (a band formed by ex-miners) plays regular concerts.