he City Center is usually defined as the area within the old city fortifications, now most distinctly recognizable by the traffic loop known as the Altstadtring, although there are many portions of the historical walls still visible. Many of the main tourist attractions can be found in the City Center. Most notable are of course the New City Hall (Neues Rathaus) with the world famous Glockenspiel, the Old City Hall, the Feldherrenhalle, the Residenz (former residence of the Bavarian kings), Nationaltheater (the opera house) and the world's most famous beer hall, the Hofbräuhaus am Platzl. Several historic churches such as the Frauenkirche, Asamkirche, Peterskirche and Theatinerkirche are also located in the city center. Three of the historic city gates still exist: Karlstor (at Stachus), Isartor and Sendlinger Tor (all are located at U-Bahn or S-Bahn stations). Several of Munich's major shopping areas are located in the City Center.