Ley tunnel

Mysterious tunnels or "secret passages" are a common element of the local folklore tradition in Europe. In Norwegian a secret tunnel-like passage is called a lønngang (lønn means "hidden" or "secret", and gang means "passage") and in Swedish a lönngång. Such tunnels are said to physically link prominent places such as country houses, castles, churches, ancient monuments and other, often medieval, buildings.

Legends about the existence of secret tunnels usually involve improbably long subterranean passages, sometimes running under major obstacles such as rivers and lakes to reach their destinations. Religious buildings, monks and the landed gentry are particularly common elements in many tunnel stories.

It is unlikely that many of the recorded tunnels exist physically, for this is a characteristic of their very nature; their significance lies in the number of similar legends of tunnels that have arisen and in connection with the more esoteric notions of channels or paths of earth energy, and such.

Underground structures have a fascination due to their being hidden from view and their contents, purpose, extent and destinations remaining unknown. Over the centuries many underground structures have been discovered by chance, ranging from Cornish Fogous, souterrains that are possibly Pictish, Roman and medieval sewers to smuggling tunnels, escape tunnels, siege tunnels, and the like.

On occasion, possible tunnels prove to be of purely natural origin, such as at Cleeves Cove cave in Scotland, or Kents Cavern in England. The site at Cleeves Cove cave was previously known as the 'Elfhouse' or 'Elfhame', the locals at that time believing that elves had made it their abode.

Rarely, natural caves or tunnel systems can be of great extent; the cave system with the greatest total length of passage is Mammoth Cave (Kentucky, USA) at 591 kilometers (367 mi) in length, whilst the next most extensive known cave is Jewel Cave near Custer, South Dakota, USA, at 225 kilometers (140 mi).

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Wikipedia