A classic showcave where the first part of the tour is through large passageways and the second half of the tour is spent walking on elevated walkways over deep pools. There are around 20 sumps on the main route through this resurgence cave, several of which are deep, some of which have nearly claimed lives. The first sump was the site of the first successful cave dive in Britain, in 1935 (a year after the first cave cave diving attempts in Swildon's Hole), and the last sump is currently the deepest sump in the UK (second deepest in the British Isles) at 90m, and the third deepest known point in any British cave at 26 metres below sea level (the fourth deepest is the Severn Tunnel Great Spring, at 25 metres below sea level). The Wookey sumps also lay claim to the first recorded cave diving fatality in UK or Ireland, of Gordon Marriott on 9 April 1949. There is an exploration description and survey online.