Subterranea are ''underground structures'', both natural (such as

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s) and human-made (such as mines). Some subterranea and related topics include:

Natural

Cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s **

Cenote A cenote ( or ; ) is a natural pit, or sinkhole, resulting from the collapse of limestone bedrock that exposes groundwater. The regional term is specifically associated with the Yucatán Peninsula of Mexico, where cenotes were commonly used ...

** Ice cave ** Sea cave **

Sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

* Karst * Lava tube **

Lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

and Martian lava tubes * Subterranean river * Subterranean waterfall * Underground lake * Volcanic pipe

Human-made or related

* Borehole * Bunker * Burial vault (tomb) * Casemate * Catacombs * Cave dweller,

Underground living Underground living refers to living below the ground's surface, whether in natural or manmade caves or structures. Underground dwellings are an alternative to above-ground dwellings for some home seekers, including those who are looking to mini ...

* Cave temple * Cellar * Dungeon * Dugout (shelter) * Fogou * Mine * Rock cut architecture,

rock-cut tomb A rock-cut tomb is a burial chamber that is cut into an existing, naturally occurring rock formation, so a type of rock-cut architecture. They are usually cut into a cliff or sloping rock face, but may go downward in fairly flat ground. It was a ...

* Smuggling tunnel * Tunnels (street tunnel, train tunnels) * Underground city, umbrella article for underground dwellings and facilities * Underground rapid transit system * Wine cave

Natural

Human-made or related

See also