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 of the witch that prompted TV's "Most Haunted" team to visit Wookey Hole Caves and Mill to explore the location in depth, searching for evidence of paranormal activity. The show, which aired on 10 March 2009, was the last episode transmitted in series 11 of the show's run on the satellite and cable TV channel Living. In 2009 a new actor to play the 'witch' was chosen by Wookey Hole Ltd amid much media interest. Carole Bohanan in the role of Carla Calamity was selected ahead of over 3,000 other applicants. The cave was first opened to the public by