During the 1950s, many countries developed large civil-defense programs designed to aid the populace in the event of nuclear warfare. These generally included drills for evacuation to fallout shelters, popularized through popular media such as the US film, "Duck and Cover". These drills, with their images of eerily empty streets and the activity of hiding from a nuclear bomb under a schoolroom desk, would later become symbols of the seemingly inescapable and common fate created by such weapons. Some Americans built back-yard fallout shelters, which would provide little protection from a direct hit, but would keep out wind-blown fallout, for a few days or weeks (Switzerland, which never acquired nuclear weapons, although it had the technological sophistication to do so long before Pakistan or North Korea, has built nuclear blast shelters that would protect most of its population from a nuclear war.)