Modlin fortress is a fortification located in the Polish village of Modlin, 30 km North-West of Warsaw, at the confluence of the rivers Vistula and Narew. This is one of the largest preserved fortresses in Poland. The fortress is still the longest in Europe – military barracks stretches at 2250 meters in length.

Location Modlin at the confluence of the rivers gave the area an outstanding defensive qualities. The functionality of this place is appreciated by the Swedish king Carl Gustav, and in which were built the first fortifications. After the Swedes fortification work continued Saxon field Marshal Adam von Steinau during the Northern war. In 1794, the Russian General Peter Suchtelen has developed a plan for a new fortress, but construction work has not begun.

The current construction of the fortress began on the orders of Napoleon in December 1806. More than 10 thousand farmers were involved in the construction of the fortress by engineer Francois Hasslo-Laubat. After the French left the castle, it was occupied by troops of the Duchy of Warsaw under the command of Hermann Dandeli. After the Polish uprising of 1830 the castle was fortified by order of the Russian Emperor. The aim was not only to protect the Western borders of Russia, but also to prevent a possible uprising. In 1834 the Modlin fortress was renamed in Modlin. The work of fortifying was headed by General Ivan Den. In the late nineteenth century in the fortress were built circular barracks with a total length of 2250 meters for up to 20,000 soldiers.

During the First world war the fortress was attacked by German forces, air attacks and was captured in August 1915. During the Second world war the fortress was holding another defense against the German army under the command of General Victor Volume.

Currently many fortifications abandoned, they gradually lose their original features. But there are examples of successful use of separate buildings of the fortress. In October 2008, the fortress was entered in the register of monuments of Mazovia. Today, the Fort offers tours where you can see the defensive barracks of the soldiers, part of the fortifications and some FORTS. Every year in Modlin fortress arranged reconstruction of the battle.