The Diamond Cave was one of the entrances to the World Beneath. It is said to be the entrance through which Arthur Denison, Oriana Nascava, Bix and Lee Crabb entered in the submersible. It is over a thousand feet below sea level, and is guarded by the Fish, an incredibly large, Dunkleosteus, a form of giant prehistoric fish, the biggest ever. This article is a . You can help My English Wiki by expanding it.