Descend into the damp subterranean world of a 4500-year-old iron and ochre mine, comprising a warren of dimly lit passageways, caverns and pools, and home to several species of bats. ‘Deep Level Caving’ sessions (adult/child £25/18) take you even further in. From November the caves are transformed into a hugely popular Christmas grotto. They’re signposted off the B4228, a mile south of Coleford.