"Every inhabitant in the country is by law required to have access to a bomb-shelter"
Quite funny, eh? For many Swiss citizens, this space is in a large civil defense shelter, but for others, and specifically non-Swiss, this shelter space comes in the form of a heavy-duty basement shelter. The bomb shelter isn't a nice-to-have or a government recommendation, but it's a mandatory requirement. That means, if you are to move to Switzerland and to build a house there, first of all you have to build a strong bunker beneath your basement. Don't think this is a simple thing. A heavy-duty bunker is very costly to build, having long and thick concrete walls along with carbon steel, vault-style doors, air filters etc.
This law is the proof that Switzerland is very serious about its civil defense and this tradition dates back to World War II, where bomb-shelters were essential against the fear of German invasion.