Mendip Hills to the development of cave diving in Britain. The first cave dive was attempted at Swildon's Hole in 1934, and the first successful dive was achieved the following year at Wookey Hole Caves, which has the deepest sump in Britain at 76 m (250 ft). The cave complexes at St. Dunstan's Well Catchment, Lamb Leer, and Priddy Caves have been identified as Sites of Special Scientific Interest. The deepest cave in the Mendip Hills is Charterhouse Cave with a vertical range of . Many caves in the Mendip area were excavated for archaeological and natural history studies by pioneer explorer
Wookey Hole Caves opened as a show cave in 1927 following exploratory work by Herbert E. Balch. As a tourist attraction it has been owned by Madame Tussauds and, most recently, the circus owner Gerry Cottle. The cave is noted for the Witch of Wookey Hole – a roughly human shaped stalagmite that legend says is a witch turned to stone by a monk from Glastonbury. It has also been used as a location for film and television productions. The show cave consists of a dry gallery connecting three large chambers, the first of which contains the Witch of Wookey formation. There are