The Bebelplatz (formerly and colloquially the Opernplatz) is a public square in the central Mitte district of Berlin, the capital of Germany. The square is located on the south side of the Unter den Linden boulevard, a major east-west thoroughfare that runs through Berlin's city center. It is bounded to the east by the State Opera building (hence its prewar name), to the west by buildings of Humboldt University, and to the southeast by St. Hedwig's Cathedral, the first Catholic church built in Prussia after the Reformation. Following the war, the square was renamed after August Bebel, a founder of the Social Democratic Party of Germany.