Reservoir Hole high and long. Prior to the discovery, the largest void under the Mendip Hills was thought to be "Main Chamber" in GB Cave, which is high. Before the find in 2012, the cave was already noted for a number of fine formations, and the newly discovered chamber, which has been named “The Frozen Deep”, contains pure-white pillars tall, as well as many stalagmites and stalactites. The possibility of a connection between Reservoir Hole and Gough's Cave, one of the show caves in Cheddar Gorge, has been raised, as the two caves are in close proximity. The stream in Reservoir Hole
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