England - Peak District to Yorkshire Dales

Not far from Castleton's town centre you come across the first of the Castleton Caves. There are four of them: the Peak Cavern, Speedwell Cavern, Blue John Cavern and Treak Cliff Cavern. They mined the rare Blue John stone at the last two caverns. It is a yellow and blue banded mineral flourite. The Peak and Speedwell Caverns were used to mine lead in the 1700s.