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
Newton St Loe SSSI history of early glaciation within South West England. The citation sheet for this SSSI describes the site as follows: The bodies of mammoths ("Mammuthus") and horses ("Equus") have been found at the site. It was not possible to identify the species however, due to the poor state of the specimens. Newton St Loe SSSI Newton St Loe SSSI () is a geological Site of Special Scientific Interest (SSSI) close to the River Avon, near the village of Newton St Loe in Bath and North East Somerset. It was notified on September 1992. It is 2.26 hectares in size. The site