Wisłoujście Fortress

Wisłoujście Fortress stands at the mouth of the Martwa Wisła River, recognizable by its central, cylindrical brick tower encircled by a low, ring-shaped artillery fort. Originally built by the Teutonic Knights in the fourteenth century to control ship traffic entering the harbor of Gdańsk, this structure has spent centuries acting as a lighthouse, a naval base, and a prison. Its base rests upon a foundation of wooden crates submerged in water, a unique engineering solution that allowed the fortress to remain stable on the marshy riverbank.