Hansaviertel. The smallest Ortsteil (district) of Berlin and is between Großer Tiergarten and the Spree River, within the central Mitte borough of Berlin.
The district was almost completely destroyed during World War II but was rebuilt from 1957 to 1961 as a social housing project by international master architects such as Alvar Aalto, Egon Eiermann, Walter Gropius, Oscar Niemeyer, Sep Ruf. Called Interbau, the whole ensemble has two churches (St. Ansgar and Kaiser-Friedrich-Gedächtniskirche). It is now protected as a historic monument.