is frequently encountered in Salzburg. Examples are the Zahnwurzen house (a house in the Linzergasse 22 in the right center of the old town), the "Lepi" (public baths in Leopoldskron) (built 1964), and the original 1957 constructed congress-center of Salzburg, which was replaced by a new building in 2001. An important and famous example of the architecture of this era is the 1960 opening of the Großes Festspielhaus by Clemens Holzmeister. Contemporary architecture Adding contemporary architecture to Salzburg's old town without risking its UNESCO World Heritage status is problematic. Nevertheless, some new structures have been added: the Mozarteum at the Baroque Mirabell Garden (Architecture Robert Rechenauer), the 2001 Congress House (Architecture: Freemasons), the 2011 Unipark Nonntal (Architecture: Storch Ehlers Partners), the 2001 "Makartsteg" bridge (Architecture: HALLE1), and the "Residential and Studio House" of the architects Christine and Horst Lechner in the middle of Salzburg's old town (winner of the architecture award of Salzburg 2010). Other examples of contemporary architecture lie outside the old town: the Faculty of Science building (Universität Salzburg – Architecture Willhelm Holzbauer) built on the edge of free green space, the blob architecture of Red Bull Hangar-7 (Architecture: Volkmar Burgstaller) at Salzburg Airport, home to Dietrich Mateschitz's Flying Bulls and the Europark Shopping Centre. (Architecture: Massimiliano Fuksas) Districts Salzburg has twenty-four urban districts and three extra-urban populations. Urban districts (Stadtteile): Aigen Altstadt Elisabeth-Vorstadt Gneis Gneis-Süd Gnigl Itzling Itzling-Nord Kasern Langwied Lehen Leopoldskron-Moos Liefering Maxglan Maxglan-West Morzg Mülln Neustadt Nonntal Parsch Riedenburg Salzburg-Süd Taxham Schallmoos Extra-urban populations (Landschaftsräume): Gaisberg Hellbrunn Heuberg Main sights Salzburg is a tourist favorite, with the number of visitors outnumbering locals by a large margin in peak times. In addition to Mozart's birthplace noted above, other notable places include: Old Town Historic center of the city of Salzburg, a World Heritage Site Baroque architecture, including many churches Felsenreitschule, an open-air theatre built in the quarry used for the construction of Salzburg Cathedral Franziskanerkirche, one of Salzburg's oldest buildings, dating from 1208 and used by the Franciscans since 1642 Getreidegasse, a busy narrow shopping street characterized by numerous high townhouses Großes Festspielhaus, an opera house and concert hall dating from 1960 and built for the annual Salzburg Festival Haus für Mozart, formerly the Kleines Festspielhaus, an opera house and concert hall dating from 1925 Hohensalzburg Fortress (Festung Hohensalzburg), overlooking the Old Town, one of the largest castles in Europe Holy Trinity Church (Dreifaltigkeitskirche), dating from