In the works on permanent loan from the GAG Immobilien AG - since 2014 in the collection of Die Photographische Sammlung/SK Stiftung Kultur - there are photographs by Werner Mantz taken primarily in the 1920s and 1930s. The images show housing estates in various parts of the city of Cologne, which were very modern at the time. Some of them were special “Das Neue Bauen” [International Style] showcase projects, for example the Weiße Stadt [White City] in Buchforst.