The Big House (Russian: Большой дом, Bolshoy dom) is an unofficial name of the building in Saint Petersburg, Russia, shared by the headquarters of the local Saint Petersburg and Leningrad Oblast branch of the Federal Security Service of Russia and the Saint Petersburg and Leningrad Oblast Main Department of Internal Affairs. The building is located in the Central District of Saint Petersburg at the beginning of Liteyny Prospekt, one block from the Neva River. It was constructed in 1931–32 in the late Constructivist style at the site of imperial Old Armoury Building which burned down in 1917. The building was designed by Soviet architects Noi Trotsky, Alexander Gegello and Andrey Ol for the use by Soviet secret police OGPU. The Big House is part of a larger complex which includes the detent