Petrovac became the first communist-run municipality in the Adriatic following an electoral victory in 1919. That auspicious event is celebrated in the Red Commune Memorial House on the waterfront, which contains a modern art gallery and revolutionary museum. The latter consists mainly of photos and documents without any English captions; it doesn't get a lot of visitors these days but the bemused staff will unlock it for you upon request.
Red Commune Memorial House
Petrovac