1918, what is known of Mendelsohn is, above all, a multiplicity of sketches of factories and other large buildings, often in small format or in letters from the front to his wife, Louise Mendelsohn (née Maas; 1895–1980). The 2011 documentary film by Duki Dror titled "Incessant Visions" is about Erich Mendelsohn and his wife, in which Dror animates the memoirs of Louise and the letters. Architecture career At the end of 1918, upon his return from World War I, he settled his practice in Berlin. The Einsteinturm and the hat factory in Luckenwalde established his reputation. The Hat Factory was commissioned in 1921, Mendelsohn's design included four production halls, a boiler, a turbine house, two gatehouses and a dyeing hall. The dyeing hall became a distinctive feature of the factory, the building was shaped with a modern ventilation hood that expelled the toxic fumes used in the dyeing process. The structure even ironically resembled a hat. As early as 1924 Wasmuths Monatshefte für Baukunst (a series of monthly magazines on architecture) produced a booklet about his work. In that same year, along with Ludwig Mies van der Rohe and Walter Gropius, he was one of the founders of the progressive architectural group known as Der Ring. His practice employed as many as forty people, among them, as a trainee, Julius Posener, later an architectural historian. Mendelsohn's work encapsulated the consumerism of the Weimar Republic, most particularly in his shops: most famously the Schocken Department Stores. Nonetheless, he was also interested in the socialist experiments being made in the USSR, where he designed the Red Banner Textile Factory in 1926 (together with the senior architect of this project, Hyppolit Pretreaus). His Mossehaus newspaper offices and Universum cinema were also highly influential on art deco and Streamline Moderne. In 1926, he bought an old villa, and in 1928, he designed Rupenhorn, nearly 4000 m2, which the family occupied two years later. With an expensive publication about his new home, illustrated by Amédée Ozenfant among others, Mendelsohn became the subject of envy. In the spring of 1933, in the wake of growing antisemitism and the rise of the Nazis in Germany, he fled to England. His assets were seized by the Nazis, his name struck from the list of the German Architects' Union, and he was excluded from the Prussian Academy of Arts. In England he formed an architectural practice with Serge Chermayeff,