This is a museum within walking distance of Stfffi's apartment along the Main River.  It was closed for remodeling the day I walked across this bridge to see it.  Note the external stairway that goes from an exterior door on the second floor, to an exterior door on the third floor.  There's no railing on the stairway, not a very safe way to get from one floor to the other.  Intriguing building, I'll try to post other copies of it.