Subterranea (geography)

Subterranea are underground structures, both natural (such as caves) and man-made (such as mines). Some subterranea and related topics include:

Natural

 * Caves
 * Cenote
 * Ice cave
 * Sea cave
 * Sinkhole
 * Karst
 * Lava tube
 * Lunar and Martian lava tubes
 * Subterranean river
 * Subterranean waterfall
 * Underground lake
 * Volcanic pipe

Man-made / man-related

 * Borehole
 * Bunker
 * Burial vault (tomb)
 * Casemate
 * Catacombs
 * Cave dweller, Underground living
 * Cave temple
 * Cellar
 * Dungeon
 * Dugout (shelter)
 * Fogou
 * Mine
 * Rock cut architecture, rock-cut tomb
 * Smuggling tunnel
 * Tunnels (street tunnel, train tunnels)
 * Underground city, umbrella article for underground dwellings and facilities
 * Underground rapid transit system
 * Wine cave