Blue John Mine and Cavern, Castleton , Hope Valley, England

The Castleton Caverns comprise The Blue John Cavern, Treak Cliff Cavern, Speedwell Cavern (all clustered around the Winnats pass) and the great Peak Cavern, just outside Castleton village.

The Blue John Cavern is at the top of the hill above Winnats Pass and is reached from Castleton either by walking up the hillside or by going up Winnats Pass and turning down the old Mam Tor road (now closed between the Blue John Mine and Treak Cliff). The cavern is open all year but opening times are restricted in January and February. Like Treak Cliff, the mine is part natural, part mine-workings, and contains natural chambers, veins of Blue John, fossils and stalactites and stalagmites. It descends a long series of steps to reach a large chamber known as Crystalised Cavern, which is followed by Lord Mulgrave's Dining-Room and the Variegated Cavern, all of which contain fine formations and interesting minerals.