Maastricht has a history of concealing, hiding and refuge, from medieval city walls to the later fortifications. These structures have defined the cityscape for centuries. Some have only been open to the public for the past decade.Air-raid shelters, bunkers, lookouts and tunnels remain hidden from us. During the Second World War, a robust underground infrastructure of shelters was established, both for people and world-famous works of art. During the threats of the Cold War, the Civil Defence (Bescherming Bevolking, or BB) made preparations in the city. After all, you never know when an emergency might come knocking. Bureau Europa has published this walk as part of its Prepper Paradise exhibition.