The film is inspired by German folklore concerning Walpurgis Night. The night from April 30 to May 1 is called Hexennacht ("Witches' Night"), and witches are reputed to hold a large celebration on the mountain peak Brocken.
The film does not specify the location of the witches' gathering, but the mountain peak depicted is implied to be the Brocken (also called Blocksberg), the highest peak of the Harz mountain range. The mountain is located in Saxony-Anhalt.