Jutting out into the sparkling Adriatic Sea, the medieval city of Dubrovnik in southern Croatia displays its centuries-old charm. Here at the heart of the city is the Old Town, paved with limestone and surrounded by medieval walls that encircle its historic core. Visitors can walk along the walls, which stretch over 6,000 feet and were built to defend Dubrovnik from pirates and other unwelcome guests during the Middle Ages. Dotted by fortifications, bastions, and towers, the walls offer breathtaking views of the brilliant blue waters of the Adriatic on one side, and the Old Town"s distinctive terra-cotta roofs on the other.