A cave or cavern was a large open underground space.
In the early 19th century, Lord Aldbourne and his followers played at devil worship in the cavern beneath the church at Devil's End. In the 20th century, the cavern was converted into a museum of witchcraft. (PROSE: The Eight Doctors)
In the 1970s, the complex in which Rudolph Steiner's Gemini Plan was being carried out had been built over a network of caves which had been an Aboriginal sacred place. The Third Doctor and Murray Stevens escaped from the complex into the caves, where they met with a group of Aborigines who agreed to help them defeat the plan. (COMIC: Gemini Plan)