St. Peter's Abbey is considered the spiritual heart of Salzburg and the oldest monastery in the German-speaking world, founded around 696 AD. The Petersfriedhof cemetery, carved into the rock of Festungsberg, contains catacombs that may date back to Early Christian times. Mozart's sister Maria Anna is buried here among aristocratic families. Visitors recognize this atmospheric location from The Sound of Music film, where the von Trapps hid from the Nazis.