“Interbau - International Building Exhibition, Berlin 1957” was held in West Berlin, Germany, from July 6 to September 29, 1957. A special exhibition under the 1928 Convention, it was organized under the aegis of the Berlin Senate with the support of Internationale Bauausstellung Berlin GmbH. Its theme was the reconstruction of the Hansa district, the Hansaviertel, and its architects described the goal as building "the city of tomorrow." The Expo welcomed 13 participants and about 1,000,000 visits.

Interbau answered two needs at once. West Berlin faced a severe housing shortage, and the Hansaviertel, on the edge of the Tiergarten, had been heavily damaged in the war. The divided city also offered a stage for competing visions: East Berlin had taken the Stalinallee as its model, and the West answered with an open, green neighborhood that rejected the traditional perimeter block. Gerhard Jobst, Willy Kreuer and Wilhelm Schliesser drew up the urban plan, Otto Bartning held overall responsibility for Interbau, and 53 architects took part. Ten landscape architects designed the green spaces, and a special exhibition, “Die Stadt von morgen” (The City of Tomorrow), drew large crowds.

The participants included many of the leading names of modern architecture. Oscar Niemeyer designed a slab of 78 apartments raised on V-shaped pillars, with a triangular elevator tower. Walter Gropius and The Architects Collaborative contributed a gently curved nine-story building with a colorful facade, and Alvar Aalto an eight-story block of 78 apartments with large patios, one of which he furnished himself. Egon Eiermann, Arne Jacobsen, Max Taut, Hans Schwippert and others completed the district, which mixed high-rise towers with single-family houses and gave priority to daylight, central heating and modern bathrooms.

Two major works stood outside the Hansaviertel. Le Corbusier's version of his Unité d'habitation, a 17-story building with 530 apartments, was built in Charlottenburg near the Olympic Stadium. The United States contributed the Congress Hall by Hugh Stubbins, a former assistant of Gropius, placed on an artificial mound so that it could be seen from East Berlin. Nicknamed the "pregnant oyster," it was given to the City of Berlin after the Expo, rebuilt after a roof collapse in 1980, and since 1989 has been the home of the Haus der Kulturen der Welt.

When Interbau opened, only about a third of its buildings were finished, and construction continued until 1960. The Hansaviertel, Le Corbusier's building and the later Academy of Arts by Werner Düttmann are now protected landmarks, and the district has been put forward on the path toward UNESCO World Heritage status. Expo 1957 Berlin turned postwar reconstruction into an international statement about how people should live in the modern city.