During the May Day holiday (from Friday , May 1 to Sunday 3 May) with a purchased unique set of tickets for entering four locations at the Belgrade Fortress, Public Enterprice gives free use of the Audio guide – a personal guide for a tour of the complex of Belgrade Fortress and Kalemegdan Park .

With the audio guide , visitors will hear a long, turbulent and glorious history of the Belgrade fortress and learn many interesting facts about this complex and 39 described locations.