Originally 7000-meters long (22 965 ft.), they consist of several parts; the Stone city walls, the Mali Ston city walls, and the Big wall with its three forts. Its forts and towers are strengthened by 10 round and 31 square flanking towers and 6 semi-circular bastions. It took almost four centuries to finish these complex defense walls, as the builders had to adapt to the rough terrain and advancements in warfare technology. The walls were last used for defense in the 19th century, and today they are a priceless monument of immense architectural and cultural value.

Constant threats coming from the far edges of the Dubrovnik area spurred its inhabitants to start building defense walls in 1333. The Big wall (1200m, 3937 ft.) at Podzvizd, built for protection from the neighboring cities, is documented to have been built in 18 months, costing 12.000 ducats. It was subsequently reinforced by the construction of three forts, the Koruna Fort in Mali Ston, the Podzvizd Fort on a hill above the city of Ston and the Veliki Kaštel Fort near the salt pans. In the Middle Ages, the city of Ston had two centers connected by the Big wall and complementing each other in function, both respecting the traditional orthogonal grid of streets and city blocks. Ston was built according to the plans approved by the Dubrovnik government in 1335 and amended in 1370 and is considered one of the best planned and best-structured cities in Europe. 

The renovation of the Walls of Ston effectively means the concurrent renovation of the town of Ston, for it is through the revival of the fortification girdle that its outer membrane and its unique medieval physiognomy are being restored. The concern for the newly purchased territory of the peninsula of Pelješac, and determination to both preserve and develop it, as well as the subsequently constructed town and the salt works, had driven Dubrovnik to execute its building undertaking in the shortest possible time. The realization of this painstakingly planned and politically-minded project, and the skill demonstrated in the construction of Ston, Mali Ston, and the complete fortification complex – from the Ston Prevlaka and the Big Sea to the Little or the Neretva Sea – clearly manifest the high level of knowledge in a settlement planning. Numerous builders, already tested in the construction of the City Walls and other structures in Dubrovnik, took part.

The town of Ston is built in a regular raster of streets, with the wider street extending in the direction north to south, while the narrower ones run vertically to them, in the east to west direction, with the main street, Placa, also stretching in the east-west direction. From the year 1333, when the construction of the Walls began, followed by the construction of both towns, the priority in the decisions made by the Government of Dubrovnik was almost without exception given to the walls and towers, while the residential buildings and public building and facilities came second – including the residence for the Rector of Ston, the cathedral of St. Blasius, Franciscan monastery, squares, and the fountain. Walls and fortifications were being constantly strengthened, heightened, added to; the street was paved, motes were dug around the walls, drainage systems were provided, the seashore was regulated and so were the streams and precipitation waters.

With some minor problems encountered due to a marshy and wet, and therefore unstable terrain on which the south-eastern section was built, along the backwater that touched the coastline, with earthquakes which caused destruction in Dubrovnik towards the end of the seventeenth century and on several occasions, later on, Ston survived until the fall of the Republic, upon which began its urban and economic stagnation.

Degradations which followed, particularly in the nineteenth century, were caused not only by the outside factors but also by the shift in the consciousness of the society as such, which today we find it difficult to explain. One such decision was to pull down a section of the Walls to build a Triumphal arch for the visit of Emperor Franz Joseph I in the year 1874. Not long afterward, in 1905, the southern stretch of the Wall – with four towers, outer walls, and ramparts – was pulled down by the citizens of Ston themselves so they could get the building material for the construction of new buildings, both public and private. That same year the new owner of the Great Castel Fortress demolished its north-western tower and in its place built a two-story building of the size and style of a barracks. Needless to say, it has disfigured the appearance of the Fortress. The awareness of the value of this fortification complex took time to build. In the years after WW2 devastation was halted, but any further activities demanded both decisions by relevant bodies and considerable funds.

The renovation of the Great Castel, the largest fortress of the entire fortification complex of Ston, was started by the Society and Lukša Beritić. Back in 1961 and until today, the reconstruction of the Walls of Ston is undoubtedly the most extensive project that the Society of the Friends of Dubrovnik Antiquities is conducting.