Croatia

Undoubted attraction of the Istrian peninsula is the smallest town in the world, Hum.

An excerpt from the article 51 facts about Croatia
It was surrounded by walls, an important strategic point on the border of the lands belonging to the Habsburgs and Venice. Today about 20 people live here in houses built of stone. The village is famous for its Glagolitic monuments (the oldest known Slavic script). The town is listed in the Guinness Book of Records.