Caves of the Mendip Hills traverse from one cave to another through the underground rivers led to the development of cave diving; the first cave dive attempt in Britain took place at Swildon's Hole in 1934. The first successful cave dive in Britain was achieved the following year at Wookey Hole Caves, where the last sump is currently the deepest in Britain at . The cave complexes at St. Dunstan's Well Catchment, Thrupe Lane Swallet, Lamb Leer and Priddy Caves have been identified as geological Site of Special Scientific Interest. There are also caves within the Cheddar Complex SSSI. A selection of the better known
Honister Crag SSSI Honister Crag SSSI Honister Crag SSSI is a Site of Special Scientific Interest in Cumbria, England. It is designated for both biological and geological interest. The site covers an area of 302.9 ha on Honister Crag and the adjacent fell Fleetwith Pike. It is separated from another SSSI, Buttermere Fells, by the B5289 road. The site is important for its plants and provides one of the best examples of species-rich upland ledge communities in West Cumbria. It supports a mixture of montane and lowland species. In 2011 Natural England successfully prosecuted Honister Slate Mine, which had been redeveloped by a