Poznan is surrounded by 18 historical forts, erected in the 19th century. The Winiary Fort called the Citadel, is the largest of these Prussian fortifications. Located on the Winiary Hill, the Citadel houses  the Armaments Museum (Muzeum Uzbrojenia), which is a branch of Wielkopolski Independence Fights Museum (Wielkopolskie Muzeum Walk Niepodleg�osciowych). On display are exhibits presenting the fightings to libetate Poznan in 1945. At the entrance to the fort, there is an open air exhibition of the military equipment from the Second World War and the post-war period.