Wiener Stadtbibliothek

The Vienna City and State Library (German: old name: Wiener Stadt- und Landesbibliothek, new name: Wienbibliothek im Rathaus), founded in 1856, is located in the city of Vienna, capital of Austria. It is the official library of the City and State of Vienna and located at City Hall. It preserves 500,000 books, 2,000 newspapers and magazines, 300,000 posters, 500,000 autographs, notable bequests and legacies and one of the most important music collections of the world. Much of the collections can be retrieved online (user interface available in German and English). The library is part of the Magistrat der Stadt Wien (Municipality of Vienna) and supervised by the City Councillor for Culture.

More information on the Wikipedia page.

The website, in German, is.