both joined the faculty of the Harvard Graduate School of Design, and became the teachers of a generation of American postwar architects. In 1937 Mies van der Rohe also moved to the United States; he became one of the most famous designers of postwar American skyscrapers. Expressionist architecture (1918–1931) Expressionism, which appeared in Germany between 1910 and 1925, was a counter-movement against the strictly functional architecture of the Bauhaus and Werkbund. Its advocates, including Bruno Taut, Hans Poelzig, Fritz Hoger and Erich Mendelsohn, wanted to create architecture that was poetic, expressive, and optimistic. Many expressionist architects had fought in World War I and their experiences, combined with the political turmoil and social upheaval that followed the German Revolution of 1919, resulted in a utopian outlook and a romantic socialist agenda. Economic conditions severely limited the number of built commissions between 1914 and the mid–1920s, As result, many of the most innovative expressionist projects, including Bruno Taut's Alpine Architecture and Hermann Finsterlin's Formspiels, remained on paper. Scenography for theatre and films provided another outlet for the expressionist imagination, and provided supplemental incomes for designers attempting to challenge conventions in a harsh economic climate. A particular type, using bricks to create its forms (rather than concrete) is known as Brick Expressionism. Erich Mendelsohn, (who disliked the term Expressionism for his work) began his career designing churches, silos, and factories which were highly imaginative, but, for lack of resources, were never built. In 1920, he finally was able to construct one of his works in the city of Potsdam; an observatory and research center called the Einsteinium, named in tribute to Albert Einstein. It was supposed to be built of reinforced concrete, but because of technical problems it was finally built of traditional materials covered with plaster. His sculptural form, very different from the austere rectangular forms of the Bauhaus, first won him commissions to build movie theaters and retail stores in Stuttgart, Nuremberg, and Berlin. His Mossehaus in Berlin was an early model for the streamline moderne style. His Columbushaus on Potsdamer Platz in Berlin (1931) was a prototype for the modernist office buildings that followed. (It was torn down in 1957, because it stood in the zone between East and West Berlin, where the Berlin Wall was constructed.) Following the rise of the Nazis to power, he moved to England (1933), then to the United States (1941). Fritz Höger was another