A-007: Erdstall Tunnels

Status and Warnings

 * Currently existing, though no new instances of A-007 are known to be under construction.
 * Validity confirmed. Origins unknown.
 * Instances of A-007 are very narrow, causing some to potentially become stuck, especially older or overweight persons. There is a chance of structural collapse in many instances of A-007. Instances of A-007 have only one concealed point of entry and no escape exists.
 * Original article by Jade.

Description
A-007, also known as Erdstall Tunnels (roughly translated as German for “earth stable” or “mining tunnel.”), are a type of tunnel found throughout Europe, likely dating back to the middle ages. Instances of A-007 are very long and narrow, having a height of 1 to 1.4 meters (3 ft 3 in to 4 ft 7 in) and a maximum width of 60 centimeters (24 in). They feature tight passages from one tunnel to a lower tunnel called "Schlupf" (slip out) that is often far too narrow for older or overweight persons, requiring a person to crawl under the slip hole, stand up, thereby sliding their shoulders through the schlupf, allowing access to the higher tunnel.

Archaeologists have given Erdtall Tunnels a rough categorization system, as follows: The anomalous property of A-007 is how inexplicable they seem to be. There is no currently known purpose for their existence, (suggestions including use as hiding places, escape routes, and places of worship), and there is almost no written documentation of their existences. There is almost no archaeological material found in the tunnels, leading experts to believe they were never used as dwellings, largely discrediting the theory that they were used as hidings in times of war.
 * Type A has a single long gallery with slip passages and short side slopes.
 * Type B has multiple levels connected at multiple places by vertical slip passages. Auxiliary construction tunnels have been found that were closed after completion. At the end of each tunnel, seating niches have been cut out or the tunnel is widened with a longer seating bench.
 * Type C has multiple horizontal slip passages and there is a round trip tunnel at the end or in the middle that is high enough to walk through upright..
 * Type D has multiple chambers that are connected through tunnels. The slip passages are mostly horizontal in this type.800px-Erdstall grundriss.jpg

History
The lack of archaeological evidence makes age determination difficult. They seemed to cease usage during the 12th century.

(The discovery of A-007 could not be found by the original author. You can help expand this page by adding to this)