Filming commenced on August 31, 1970 and ended on November 19, 1970. The primary shooting location was Munich, because it was significantly cheaper than filming in the U.S., and the setting was conducive to Wonka's factory. Stuart also liked the ambiguity and unfamiliarity of the location. External shots of the factory were filmed at the Munich Gaswerks; the flats and clock tower still exist.
The clock tower is on the other side of the newer buildings to the east.