Something is missing here, and it’s not just all the people, though their absence is unmistakable from a deserted Fifth Avenue, a vacant New York Stock Exchange and along the West Side Highway, which is empty of all but a few ominous figures in uniform .

In these New York Times photographs, taken during mandatory civil defense drills in the fervid early years of the Cold War, you can almost hear the absence of sound. All the rumbling, honking, chattering, clattering noise of everyday life has suddenly paused as the city goes into hiding — leaving the click-click-click of a traffic signal or the flutter of a pigeon at Penn Station audible now, in eerie relief.

But even in the photos that show New Yorkers scrambling for cover in the streets or peering up from the shelter of a subway station, the terror that they’re running from is missing, like King Kong erased from the frame. It’s the threat of atomic annihilation, nebulous and unseen.