MRU, Petla Nietoperska
There are munition storage rooms by unfinished bukers in one of branches of the central corridor, a loop with many no-through rooms. Not far away from there, about 30 meters to the surface and 20 minutes of walking lies a village of Nietoperek ("Bat"). The same name has also the natural preserve established undrground, which is said to be the largest bat preserve in central Europe.