7. Novi Sad & Sremski Karlovci
On the banks of Danube, but at the historic crossroads of empires, cultures and religions, Novi Sad grew to become a truly multicultural European city. Explore its busy pedestrian walkway and its remarkable churches and synagogue. Visit the house of Mileva Einstein, and a local beach. Across the river, marvel at the Gibraltar of Danube, the Petrovaradin Fortress, then head to Srijemski Karlovci. On the leafy hillside, this charming baroque town is the center of culture and spirituality, and often lovingly called 'museum town's for its authentic historical ambiance.