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 resurgences. In particular, the passages in the 20th chamber are interpreted as a former Vauclusian spring, the waters of which once surfaced in the Ebbor Gorge. It is uncertain whether that was the original rising or whether it formed when the main rising at Wookey was blocked. The current resurgence is located close to the base of the Dolomitic Conglomerate at the head of a short gorge formed by headward erosion with subsequent cavern collapse. The morphology of the passages is determined by the rock strata in which they are formed. The streamway in the outer part of the cave