English: Another bus shot but what a interesting place this would be to visit..... The Walls of Ston are a series of defensive stone walls, originally more than 7 kilometres (4.3 mi) long, that surrounded and protected the city of Ston. They were built to protect the precious salt pans that contributed to Dubrovnik's wealth, which are still being worked today. The Walls of Ston were known as the "European wall of China".