Karlsplatz is an important traffic junction and close to various places of interest. It is located at the bustling transition between the inner city and the fourth district. In the late 19th century the square was erected on the former riverbed of Wienfluss, which was regulated and canopied. Karlsplatz lies at the foot of the massive and splendid Karlskirche, that was commissioned more than a century earlier by Emperor Karl IV after the cessation of a pest epidemic. Vienna’s largest baroque church was built by architect J.B. Fischer von Erlach between 1716 and 1737. Its green, 236 feet or 72 meters high copper dome outshines Karlsplatz and its surrounding buildings. Art-Nouveau-style Otto Wagner Pavillon with Club U, historic Wien Museum, project space, Künstlerhaus, brut and the Technical University are situated on or in the vicinity of the square. Yet the area is not just about culture and entertainment. In and around the busy underground pedestrian passage homeless people and drug addicts gather. The square and its environment have experienced various transfigurations and even though the underground passage shall be redesigned in the near future, there is still a social problem to be solved. A successful measure for cultural stimulation of the square came from the project group karlsplatz.org. At the fountain in front of Karlskirche and in adjoining Resselpark (park named after the inventor of the ship propeller – Joseph Ressel) stages were erected for musical performances in summer. In winter the square is converted into a big Christmas market. On bales of straw we staged SoKo.