Castleton
Castleton in the Peak District is one of the most comprehensively interesting villages in the national park, a settlement in the Hope Valley beneath Mam Tor whose combination of the remarkable concentration of show caves, the ruins of Peveril Castle on the limestone ridge above the village, the Blue John mineral unique to this area and the walking available on the surrounding gritstone and limestone hills creates a destination of exceptional variety and scientific interest. The four show caves accessible from the village represent different aspects of the remarkable cave system that honecombs the limestone below Castleton.
Peak Cavern, accessible from the village centre through a dramatic gorge entrance, is the largest natural cave entrance in Britain, its great arched opening once housing a rope-making village of considerable complexity. The Blue John Cavern and Treak Cliff Cavern contain deposits of Blue John, a semi-precious fluorspar mineral found only in the mines of Castleton and unique to this area of Derbyshire, whose purple and yellow banding has been worked into decorative objects since the Roman period. Speedwell Cavern, entered by boat along an underground canal, provides a different and entirely memorable cave experience.
Mam Tor above the village, its summit accessible by a fine ridge walk, provides outstanding views of the Hope Valley and the contrast between the limestone White Peak to the south and the gritstone Dark Peak to the north, one of the most informative single viewpoints for understanding the Peak District geology.