Barbarastollen, Mining museum at University of Cologne, Germany.

The Barbarastollen is a 40-metre replica of a coal mine gallery in a cellar room beneath the University of Cologne's main auditorium. The painter and graphic artist Kurt Holl designed it using real coal from the Aachen coalfield glued to the walls with tar. Companies supplied original equipment, tools and machines from coal mining.

The tunnel was built in 1932 during the construction of the University of Cologne as a teaching and demonstration object for students of the Faculty of Economics and Social Sciences, continuing the tradition of the Museum of Trade and Industry of the Cologne Commercial College. After decades of oblivion, the entrance hidden behind a shelf was rediscovered in the early 1980s. From 1984 it was restored under Claus Piekarski and the Ruhrkohle AG and reopened to the public.

The underground passage displays communication devices, hand-operated mining tools, and transport methods that show how coal miners worked below ground. Visitors can observe the daily routines and challenges these workers faced during their shifts.

The show mine lies in a cellar room beneath the university's assembly hall (Aula), not the main building. Visitor groups can enter only by arrangement with the Institute for Occupational Medicine. The roughly 40-metre passage is a replica, so expect a confined indoor space rather than a working pit.

The show mine holds an official mining-law permit even though no minerals are extracted there. On tours, guides like to note that this permit leaves the University of Cologne with little say over operations in its own basement room.