Ключевые слова: active, activity, architecture, background, backhand, belgrade, belgrade fortress, belgrade serbia, belgrade tennis, beograd, brick wall, capital, castle, citadel, city, clay, clay court, clay tennis, club, court, europe, exterior, famous, forehand, fort, fortress, historic, kalemegdan, kalemegdan park, leisure, medieval, novak djokovic, old town, outdoor, park, people, play, ramparts, recreative, red clay, serbia, serbian, singidunum, sport, sports, srbija, tennis court, tennis net, walls, yugoslavia,