In this Tuesday, Sept. 26, 2017 photo, Derek Boese, the Chief Administrative and Public Information Officer for the Southeast Louisiana Flood Protection Authority-East, uses a flashlight to illuminate the stair well of a Cold War era Civil Defense bunker in New Orleans. In a real nuclear disaster, taking cover in a building bearing a rusted yellow fallout shelter symbol may not be the best option anymore. Experts say the shelters in schools and courthouses are often aging relics from the Cold War that haven’t been maintained. And conventional wisdom has changed. (Max Becherer /The Advocate via AP)
In this Tuesday, Jan. 16, 2018 photo, a fallout shelter sign hangs on a building on East 9th Street in New York. The fallout shelters, marked with metal signs featuring the symbol for radiation — three joined triangles inside a circle — were set up in tens of thousands of buildings nationwide in the early 1960s amid the nuclear arms race. In New York City alone there were believed to be about 18,000. (AP Photo/Mary Altaffer)
NEW YORK — A generation of Americans knew just what to do in the event of a nuclear attack — or during a major false alarm, like the one over the weekend in Hawaii. Take cover in a building bearing a yellow fallout shelter symbol.