The Boyen Fortress was built between 1844 and 1856 to protect the kingdom’s border with Russia, and was named after the then Prussian minister of war, General Hermann von Boyen. Since the frontier ran north−south along the 90km string of lakes, the stronghold was strategically placed in the middle, on the isthmus near Giżycko, situated by the lake to the west of the town centre.
The fortress, which consists of several bastions and defensive towers surrounded by a moat, was continually modified and strengthened, and it successfully withstood Russian attacks during WWI. In WWII it was a defensive outpost of the Wolf’s Lair, given up to the Red Army without a fight during the 1945 offensive. The fortifications have survived in surprisingly good shape, and some of the walls, bastions and barracks can safely be explored. Inside the museum you’ll find a scale model of the fortress and a few odd items, such as a section of wall with a Russian soldier painted on it, used as target practice by the Prussians.