If you like history, then you must visit the Citadel Of Alba Iulia. One of the lasts Star-shaped Citadel' s of the world, where the history come to live every weekend like Romans fights, slaves market or the ceremonial of changing of the guards.
You can have a rest, eat or drink something while visiting the area at one of the restaurants or cafe- bar and admire what the Romans build in the old times.
I will certainly visit it any time i can. <3