It may also interest you the fact that Switzerland in the '60s made it mandatory to add a bunker in large homes and residential buildings, up until a few years ago. Oh, and they kept all their bridges mined (possibly road and railway tunnels too, IIRC), in case they needed them gone in case of an invasion. The plan was for the entire population to seek refuge in the bunkers and to basically cut off the country from the rest of the world, in case the Cold War suddenly became Hot.

They also have a lot of bunkers and installations inside mountains. I know of at least one been re-purposed as a highly secure datacenter, privately owned.