Description: This cave was formally known as the 'Devils Arse' before being called Peak Cavern. It is in the centre of the village, right underneath Peveril Castle. It has the largest natural cave entrance in Britain and the second largest in the world! It even claims to have had a pub in it at one time. The stream that drains from Peak Cavern through the village is claimed by local legend to result from Satan urinating inside the cavern ! The underground river (called the River Styx) formed the cave, and as the cave grew, the first part of the cave ceiling collapsed. A small gorge was formed which leads to today's cave entrance, 20 m wide and 30 m high below a high limestone cliff. The room behind the entrance is more than 100 m long and was used by the inhabitants of Castleton for several hundred years. The cave is a shelter against rain and was the largest 'dry' place on the isles for a very long time. The damp atmosphere made it ideal for rope making, the remains of which can still be seen today. (extracted from www.showcaves.com)