Subterranea refers to underground structures, both natural (such as caves) and man-made (such as mines). Some subterranea include: \n* Bunker \n* Burial vault (tomb) \n* Casemate \n* Catacombs \n* Caves \n* Ice caves \n* Cave dweller, Underground living \n* Cave temple \n* Cellar \n* Cenote \n* Dungeon \n* Dugout (shelter) \n* Karst \n* Gallery \n* Lava tubes \n* Lunar lava tube \n* Rock cut architecture, rock grave \n* Smuggling tunnel \n* Subterranean rivers \n* Tunnels (street tunnel, train tunnels) \n* Underground city \n* Underground lakes \n* Underground rapid transit systems \n* Volcanic pipes \n* Wine caves