The sound of music lures fans both of classical music and of Julie Andrews to Salzburg. Most sites are within walking distance of the city center. Salzburg Cards allow free bus travel and some discounted admissions. Sound of Music Tours, venues such as Grosses Festspielhaus and visits to Mozart's residence and birthplace set the tone for most visitors, but the city also boasts fortresses, abbeys and castles for the architecturally inclined. The young at heart should scamper to the Toy Museum.