There are four show caves open to the public in and around Castleton. These are Peak Cavern, Speedwell Cavern, Treak Cliff Cavern and Blue John Mine.
Peak Cavern is the only wholly natural cavern of the four and is the least commercialised. It was known to locals as the Devil’s Arse and the stream issuing from it as the Styx, which give some idea of how the locals used to feel about it.
The approach and entry are very impressive, taking you into an immense cleft in the rock below the crag on top of which sits Peveril Castle and into a wide and spacious cave entrance.
Beyond this lie miles of passages though the standard tour only goes a few hundred metres into the cavern.
Speedwell Cavern lies at the foot of Winnats Pass and is probably the most popular cavern of the four. This is a mine with several natural chambers and an underground canal which forms the centrepiece of the visit.
Steps lead down from the entrance to the canal, where visitors take a boat trip leading eventually to the Bottomless Pit, a large water-filled natural cavern so high you cannot see the top.
Treak Cliff Cavern is higher up the old Mam Tor road and contains a range of nice stalactite and stalagmite formations. The cave was originally a lead mine, but now mines Blue John. The initial sections of the cave pass through the old mine workings and veins of Blue John stone can be clearly seen in the walls.
Blue John Mine lies just below the crumbling face of Mam Tor and is approached via Winnats Pass. 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 several large chambers, all of which contain fine formations and interesting minerals.