Although the Zollverein in Essen started in 1847, it was with the foundation of Zollverein XII in 1932, creating the largest coal mine in the world, that the rationalisation and integration of work processes were combined with the aesthetics of the architecture. The architects, Fritz Schupp and Martin Kremmer, inspired by the Bauhaus style, created the buildings following the principles of symmetry. Zollverein XII remained in operation until 1986.