Mills are an impressive testimony to man’s inventiveness, and represent an important feature of technical development. A Swiss Mills Day is organized every year in order to demonstrate the importance of these cultural assets. The Ballenberg mills will also be in action: the water-driven saw mill from Rafz, Zurich (691) and the two Valais mills from Naters, Valais (1122) and Törbel, Valais (1121).