International Fortress Day

Once a year, the Day of the Forts provides a precise look at the architectural structures that played a key role in shaping Cologne's development in the 19th and early 20th centuries. On this day of action, various forts, intermediate works and other fortifications open their doors to take visitors to places that seem barely perceptible in the urban fabric and yet are of considerable historical relevance. The guided tours and accompanying contributions illustrate how the Prussian military engineers designed a widely ramified defense system that once surrounded Cologne in a ring and whose structural remains remain today as monuments in the countryside. At the same time, it shows how functional military architecture has been transformed into spaces of cultural mediation over the decades. The Day of the Forts focuses on this transformation: it shows how former defensive structures have become places of collective remembrance and civic engagement. Each year, the program changes to highlight these historical sites in new ways, inviting visitors to take a differentiated look at the background to the city's history.