In its building opposite the Neue Nationalgalerie, the library holds some 3.7 million volumes; a lovely scene from the Wim Wenders film, Wings of Desire, was shot in the reading room. Its treasures are kept behind thick walls on a second site (Unter den Linden 8): old maps, early printed books and original music scores by composers such as Bach and Schumann. Founded in 1661 by the Great Elector, the Prussian State Library was built between 1903 and 1914.