Erdstall
An erdstall is a type of tunnel found across Europe. They are of unknown origin but are believed to date from the Middle Ages. A variety of purposes have been theorized, including that they were used as escape routes or hiding places, but the most prominent theory is that they served a religious or spiritual purpose. Etymology There are very few historic references – a document from 1449 names the area above the tunnels as (lit., "atop the soil tunnels"). Although the modern term uses (stable, shed), this stems from the word (spot, location – cognate to the English "stead") and the related ("tunnel in mining"), and this is combined with (soil, ground – cognate to the English "earth"). Alternative regional names are (Bavaria), and (Austria), that carry the regional names for dwarfs that folk belief has connected them to. Construction Erdstalls are very low and narrow – they have a height of and a maximum width of about . Additionally, they feature very tight passages connecting one tunnel to a lower tunnel called a (slip out), which are typically extremely narrow and impassable for some, as crawling under the slip hole, and then standing up to slide the shoulders