The old walled town of Budva with the Citadela in the foreground, Budva, Montenegro, Europe

Getty Images/Robert Harding World Imagery

The citadel at the Old Town’s seaward end offers striking views, a restaurant and a library full of model ships, rare tomes and maps displayed safely behind glass. It's thought to be built on the site of the Greek acropolis, but the present incarnation dates from the 19th-century Austrian occupation.