High Quality Content by WIKIPEDIA articles! The Walls of Ston are a series of defensive stone walls, originally more than 7 kilometres (4.3 mi) long, that have surrounded and protected the maritime city-state of Dubrovnik (Ragusa), situated in southern Croatia.Despite its small size, the Republic of Dubrovnik was well protected by massive city walls and used Pelje ac to build another line of defense. At Pelje ac's narrowest point, just before it joins the mainland, a wall was build from Ston to Mali Ston.Today's 5.5 kilometre (3.5 mile) long wall that links these two small communities is in the shape of a pentagon was completed in the 15th century, along with its 40 towers and 5 fortresses. The wall meant to protect the precious salt pans that contributed to Dubrovnik's wealth, which are still being worked today. It is the second longest wall in Europe, surpassed only by Hadrian's Wall between Scotland and England.