I’ve always had an abiding interest in the history and culture of the Cold War, that nearly fifty-year span of the 20th Century when the United States and Soviet Union vied for global power and threatened each other, and the world ,with nuclear obliteration. It’s also chilling to learn how each country busily made plans to try to survive an atomic holocaust by creating civil defense programs, building bomb shelters and developing warning systems and evacuation plans for major cities.

Artifacts of that chapter of Cold War history can be still be found in neighborhoods across Los Angeles in the forms of long-neglected civil defense sirens sitting atop now rusty towers. During the height of the Cold War there were more than 250 civil defense siren towers, which, when activated, were supposed to alert people about a coming Russian attack so they could find shelter.

They don’t work now, but during the era when World War III looked like it could break out at anytime, the sirens were supposed to warn people about an impending nuclear attack. If people heard the sirens blare, they were supposed to seek shelter until after the atomic bombs had fallen. (Of course no one knows what people were supposed to do after L.A. had been turned into a prairie of nuclear ash.)

One man who’s fascinated with these old sirens is Dennis Hanley. As a self-described siren hunter, he’s spent years finding and mapping L.A.’s old civil defense sirens and taking photos of them.

Listen to my profile of Hanley’s work and learn more about L.A.s civil defense towers below:

If you want to hear more sounds of the Cold War, from civil defense messages to groovy music, check out Conelrad, a website that pays homage to Cold War pop culture. If you want an example of how Americans were preparing themselves for surviving a nuclear war, check out this civil defense PSA from the early 1950s. It’s called “Duck and Cover” and is aimed at school kids.