Switzerland: Secret bunkers and nuclear shelters become hotels and cheese factories

During the Second World War, Switzerland had a network of around 8,000 bunkers and military shelters. After Germany invaded France in 1940, the famously neutral Switzerland was surrounded by Axis powers and recognised it would be out-gunned in any assault. To hold off an invasion, Switzerland sought to make itself prohibitively difficult to conquer.

Under a plan dubbed the National Redoubt, much of the country's manpower and firepower would retreat to the mountains if a foreign aggressor attacked. Through its chain of fortresses and bunkers, Switzerland would keep control of the mountains along with key transit routes. During the Cold War, concerns turned to nuclear attack. The Swiss ramped up military spending and many homes were required to be equipped with bomb shelters.

In more recent years, though, due to high maintenance costs and a cooling threat of invasion, the Swiss Army has tasked a property company with trimming the number of bunkers down. Dotted around Switzerland, often disguised as barns and houses, the vast majority have now been bought, sealed off or set aside for historical preservation.

Many of the former strongholds have been transformed and refashioned into business such as data centres, hotels, museums and even mushroom farms and cheese factories. Swiss mushroom producer Gotthard-Pilze produces some 24 tonnes of shiitake mushrooms per year in 11 former bunkers.

For upwards of almost $200 a night, guests at a Swiss hotel might expect to catch a glimpse of the towering Alps or overlook one of the country's famous lakes. But visitors to Hotel La Claustra get a room without a view. The 17-room hotel is buried in the Gotthard mountain range and, with cavernous walls and minimalist interior, offers the chance to spend a few nights in an ex-army bunker.