If one were prone to nuclear anxiety, a state of mind perhaps more commonly associated with the height of the Cold War than with the 21st century, this week's news might be reason to consider taking whatever steps possible to prepare for the worst.
With North Korea threatening to attack Guam, President Donald Trump has tweeted that "military solutions" are "locked and loaded." Already, Hawaii has unveiled a plan to prep citizens for an attack by missile. Though Hawaiian authorities have specified that their plan is not the same as the famous "duck and cover" of 50 years ago, it's not hard to see why — given North Korea's reported nuclear capabilities — the thought of such an attack might spark thoughts of the type of nuclear preparedness measures that were taken by then.
But one of the most stereotypical such symbols of the nuclear age has largely been abandoned as a safety tactic. Though the backyard bunker lives on in the American imagination, in reality its heyday was brief.
As TIME has previously reported, it was already clear in the 1950s that people who found themselves near ground zero in a nuclear attack could probably not be much helped by the kinds of structures that might be designed to protect large groups of people in cities. In 1957, the group known as the Gaither Committee issued a report to President Eisenhower enumerating the many problems with a safety program that focused on such shelters. They were prohibitively expensive, it was impossible to know whether they'd be located in the right places until it was too late, and even if they were well placed there wouldn't be enough time for a substantial number of people to get inside in time. (Of course, individual bunker-builders' concerns are different from those of the federal government, as one's own home is always the right place for one's own personal shelter.)
However, some people believed that a "fallout shelter" — as opposed to a "blast shelter" — might still be able to save the lives of people who were farther away from the impact but who would have otherwise been affected by the aftereffects of a nuclear attack. "The Panel has been unable to identify any other type of defense likely to save more lives for the same money in the event of a nuclear attack," the Gaither Committee declared. But there was no consensus on how much of a difference they would make, at first few actual steps were taken to build those shelters, even though the Federal Office of Civil and Defense Mobilization issued specifications for a cheap DIY shelter in which Americans could hunker down for the two weeks after an attack, after which they could safely — it was then thought — emerge.
It was in the early 1960s — as the Cold War entered one of its tensest phases — that people began to take the idea of building their own fallout shelters more seriously, as TIME reported in 1961. The government requested $207.6 million (the equivalent of about $1.7 billion today) to spend on a fallout shelter program, which would designate and mark the community shelters that already existed, stock up on supplies and help citizens prepare to go underground. Meanwhile, individuals, encouraged by President Kennedy's call for preparedness, started building their own, with sales of shelter-building necessities skyrocketing.
In 1961, the Department of Defense published a handy pamphlet instructing Americans about what to do to protect themselves from fallout. Though the pamphlet emphasized community and public shelters as the most efficient tactics, it also included tips for at-home shelters that could be built for $150 or less and would cut the danger from fallout, the Department asserted, by 100 times.
"In the event of a nuclear attack, be prepared to live in a shelter for as long as two weeks, coming out for short trips only if necessary," the pamphlet continued. "Fallout would be most dangerous in the first two days after an attack, and even if you were inside a shelter you probably would have absorbed some radiation. Your freedom of action would depend on your radiation exposure during the critical period after the fallout descends. So, never expose yourself unnecessarily to radiation."
However, within about a year, the vogue for shelters was already on its way out.
" Shelters against atomic and hydrogen bombs are nothing but coffins and tombs prepared in advance," the Soviet Minister of Defense was quoted saying in early 1962. "There is no bunker, not even hermetically sealed, where one could sit quietly through explosions of atomic and hydrogen bombs."
Not every scientist studying the matter agreed, but a consensus was beginning to emerge: the facts of nuclear war — not only the radiation but also the strategy of mutually-assured destruction — were such that a shelter couldn't do much good. People would have to stay underground for much longer than two weeks to be safe, and during that time the quick-and-cheap home shelters people had been encouraged to build would rarely suffice. (For example: the 1961 government pamphlet instructs those building their own shelters to make sure they have at least a metal pail with a lid for "sanitary" needs; imagine being underground with several people for several months and one metal bucket.) Plus, improving nuclear technology meant that smaller shelters could be quickly rendered obsolete. And, perhaps as importantly, the immediacy of the threat faded a bit. The shelter program that had once seemed to be such a priority languished in Congress — and Americans' appetite for living in a constant nuclear shadow faded.
Bunker technology has changed, as has missile technology, in the intervening years. The signage that was posted in the 1960s may remain, but many of those shelters are no longer equipped to do their job. Some individuals devoted to disaster preparedness continue to build their own shelters, but the national fallout shelter conversation largely came to an end — at least temporarily.