Fluorspar and baryte mine Käfersteige near Pforzheim Germany. Tunnel from 1990.
Hans-Peter Scholz <a href="//commons.wikimedia.org/w/index.php?title=User:Zwergelstern&amp;action=edit&amp;redlink=1" class="new" title="User:Zwergelstern (page does not exist)">Ulenspiegel</a>
CC BY-SA 2.0 de
contributed by the author