On the salt has thrived Dubrovnik Republic. Ston was the second city in importance in it, and had an exceptional strategic role at a time when salt was tender. So it had to be fenced by walls, so large that only one that is bigger is Great Wall of China. It was completed in the 15th century. This fortification system, known for its defense and urban solutions, is 5,5 kilometers long. The walls begin or end with two large towers, Koruna in Mali Ston and Veliki Kaštil in Ston, and the third, most monumental is Bartolomeo on the hill above Ston. The Walls of Ston are known as the ‘European wall of China’.