The area around Castleton, in the Hope Valley, contains the most famous manifestations of the geology of the Peak District. A number of caves and mines are open to the public, including some former lead mines and Blue John mines (amethystine spar; the unusual name is a corruption of the French bleu-jaune, meaning "blue yellow"). The limestone caverns attract many people, which means that pretty Castleton is marred by a certain commercialization. Summer brings the crowds, many of which poke around in the numerous shops displaying Blue John jewelry and wares.
For me, it was Borealis or bust--or both.More