Split

Split needs 2 days: Diocletian's Palace (a 4th-century Roman palace turned into the city's living heart) on one, and nearby beaches or a ferry trip to the Dalmatian islands on the other. June-September brings the best Adriatic weather. It's cheaper than Dubrovnik, with a more local, less tourist-saturated feel. Its Diocletian's Palace, a UNESCO World Heritage Site, is unique in the world: not a ruin to visit but a Roman palace where people still live, work and run businesses, with streets and houses built literally within its walls.