Why does Switzerland have so many bunkers?

What we’re visiting today is not the Sonnenberg bunker qua bunker, but rather the former command center — the seven-story, subterranean cement bloc where emergency squads were meant to implement the technical and logistical operations that sheltering 20,000 people underground entails. The original civilian “bunker,” in fact, is no less than the four lanes of traffic whizzing below our feet: An underground highway, the Sonnenberg Tunnel was conceived in the 1970s to ease traffic flow through mountainous central Switzerland, but when construction coincided with national efforts to bolster civil protection, the twin throughways were reinforced to serve a second purpose as emergency shelter space. In the event of a nuclear attack, traffic would halt, and instead civilians would stream in, sealing off the tunnel entrances with the aid of four concrete doors 1.5 meters thick and capable of withstanding a nuclear detonation at a distance of 1 kilometer. The command center overhead stocked a w ... Read full article.