Kölner Festungsmuseum

Housed in one of Cologne's Prussian fortifications, Zwischenwerk VIII b in the former outer fortress ring at Marienburg, this museum documents the city's wider defences. Guided tours cover the grounds with park, moats and sculpture park, then a demonstration of the last surviving drawbridge of its kind in Germany. Inside, rooms from the guardroom to the powder magazine are explained. Volunteers have run it since 2004.