Titan

Titan is a natural cavern near Castleton in the Derbyshire Peak District, and is the deepest shaft of any known cave in Britain, at . following its discovery on 1 January 1999 after cavers discovered connections from the James Hall Over Engine Mine to both Speedwell Cavern and Peak Cavern. Previously, the deepest known underground shaft in Britain had been Gaping Gill on the slopes of Ingleborough in the Yorkshire Dales.