Souterrains are human made subterranean structures like quarries, mines, waterwells, road- and railway tunnels, underground aquaducts, catacombes, military underground defence system, troglodyte dwellings etc. They can be found all over the world and they form a very special study object as the area's one can encounter are varied. It ranges from biology, history, mining-engineering, archaeology, speleology, geology, and many more. Souterrains are studied by many people all over the