Fort IV

Fort IV stands in Bocklemünd on Cologne’s western bank of the Rhine, as part of the former inner ring of fortifications. Built between March 1874 and 1876, the large artillery fort covered about 330 by 210 metres, with walls one to three metres thick and a dry moat nine metres wide. Its original design combined artillery with infantry support, while neighbouring forts stood roughly 2,550 and 3,150 metres away.

Stronger ammunition brought a reinforced kehlblockhaus, armoured observation domes and strengthened caponiers. From 1909 until 1914, Airship Battalion No. 3 used the site because of its proximity to Cologne’s airship port. After the Treaty of Versailles led to dismantling in 1921 and 1922, the preserved rear barracks became a sports facility, with casemates serving as changing rooms, a gymnasium and showers. Later uses included emergency housing, mushroom cultivation, a poultry farm and city workshops, while wartime air-defence adaptations remain visible.

Today, sport occupies the main part of the complex, and the surviving underground spaces sometimes open during special events. The layered ceilings combine brickwork, sand, concrete and earth, preserving a tangible record of how military architecture adapted to civilian life.