The former City of Bonn tram depot (Straßenbahndepot der Stadt Bonn) stands at Graurheindorfer Straße 157 in Bonn's constituent community of Bonn-Castell. For its time, it is an important example of industrial Art Nouveau architecture,[1] is legally protected[2] and since 2000 has been used as an office building.[3] Housed in the old tram depot is the Pädagogischer Austauschdienst, a section of the Kultusministerkonferenz secretariat that took up residence there in 2010.[4]