Duck and Cover was a suggested method of personal protection against the effects of a nuclear detonation which the United States government taught to generations of United States school children from the late 1940s into the 1980s. This was supposed to protect them in the event of an unexpected nuclear attack which, they were told, could come at any time without warning. Immediately after they saw a flash they had to stop what they were doing and get on the ground under some cover—such as a table, or at least next to a wall—and assume the fetal position, lying face-down and covering their heads with their hands. Similar instructions were given in 1964 in the United Kingdom by Civil Defence Information Bulletin No. 5. and, in the 1980s, by the Protect and Survive series.
Critics have said that this training would be of little, if any, help in the event of thermonuclear war, and had little effect other than promoting a state of unease and paranoia.
The United States' monopoly on nuclear weapons was broken in 1949 when the Soviet Union tested its first nuclear device, and many in the government and public perceived that the United States was more vulnerable than it ever had been before. Duck-and-cover exercises had quickly become a part of Civil Defense drills that every American citizen, from kids to the elderly, practiced so as to be ready in the event of nuclear war. In 1950, during the first big Civil Defense push of the Cold War; the movie Duck and Cover was produced (by the Federal Civil Defense Administration) for school showings in 1951. At the time, it was believed the main dangers of a Hiroshima-type nuclear blast were from heat and blast damage: radioactive fallout itself was not clearly identified until 1954, after the Castle Bravo nuclear-weapon test in the Marshall Islands caused sickness and death in Japanese fishermen on the Lucky Dragon fishing vessel.