Cheddar Complex Cheddar Complex The Cheddar Complex is a 441.3 hectare (1090.5 acre) biological Site of Special Scientific Interest near Cheddar around the Cheddar Gorge and north east to Charterhouse in the Mendip Hills, Somerset, notified in 1952. The very large area includes 4 SSSIs formerly known as: Cheddar Gorge SSSI; August Hole/Longwood Swallet SSSI; GB Cavern Charterhouse SSSI; and Charterhouse on-Mendip SSSI. It is part owned by the National Trust, commercial landowners including the Marquess of Bath's Longleat Estate; and part managed by the Somerset Wildlife Trust. The Cheddar Complex supports a wide range of semi-natural habitats which includes unimproved grassland,
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