Blue John is only found beneath Treak Cliff Hill, near Castleton, and gets its name from its distinctive colour. It is now only mined in two caverns - Treak Cliff Cavern and Blue John Cavern.

It's just a short distance from the villages of Hope or Castleton, where a cosy pub or two await with a well-earned pint or roast dinner. Reviews suggest car parks can fill up quickly at peak ...