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
Cheddar Complex calcareous dry dwarf-shrub heath, semi-natural broadleaved woodland and dense and scattered scrub. Four nationally rare plants are present, including Little Robin "Geranium purpureum", Cheddar Pink "Dianthus gratianopolitanus" and Cheddar Bedstraw "Galium fleurotii", two of which are endemic to the Cheddar area, as well as fifteen nationally scarce species. This site is important for karst, caves and vertebrate palaeontology and comprises four single interest localities. Cheddar Gorge is Britain’s largest gorge and probably the country’s best known limestone feature. It is a spectacular fluvial feature with a geomorphic history extending back 2 million years and encompassing the major environmental changes of