The biggest natural cavern in Derbyshire, with the largest entrance to any cave in the British Isles. Site contains information on location and admission prices.
http://www.peakcavern.co.uk
Offers a unique boat journey through the workings of a 200 year old underground lead mine which opens into a network of natural caverns and underground rivers. Details of opening times and prices.
http://www.speedwellcavern.co.uk/
The only place in the world where Blue John Stone naturally occurs. Ancient underground caves open all year round. Online tour, information on shop and mail order service.
http://www.bluejohnstone.com/