In 1333, the Republic of Ragusa (Dubrovnik) acquired Pelješac Peninsula. To protect its boundaries, Dubrovnik founded the towns of Ston and Mali Ston, one on each side of the peninsula, and connected them with a complex fortification system, effectively closing off Pelješac from the hinterland. Sometimes compared to the Great Wall of China, Ston’s walls run 5.6km (3 1/2 miles) up and over the hill between the two towns. The climb up is quite steep, and there are many steps, but from atop the walls you get amazing views over the surrounding landscape. Southwest of Ston, note the vast expanse of salt pans. The Romans were already collecting salt here, but it was under Dubrovnik that the industry really expanded, as salt was in high demand for export and reaped considerable profits. As you walk the walls and cross over to the opposite side of the peninsula, you have views down onto the bay of Mali Ston, with its extensive shellfish farming. Allow 45 minutes to complete the hike, wear good walking shoes, and carry a bottle of water.