The decision to build the Eastern Breakwater was taken in 1818. Due to the serious silting of the Świna River on the side of the sea the Prussian King Frederick William III issued an order to erect breakwaters. Choice of the building material posed a problem. Finally it was decided that erratic blocks would be used, the biggest of which weighed 1500 kg. Construction of the breakwater was completed in 1823. The Eastern Breakwater is of impressive dimensions. It is the longest stone breakwater in Europe. It is 1400 m long, 7 m wide and rises 3 m above the water level. In the 1980s the structure was strengthened with a coat of reinforced concrete which irrevocably concealed the beauty of the natural building material.