In 1976, radio operators across the world began hearing a strange, relentless tapping—dubbed the “Russian Woodpecker.” What sounded like an electronic pulse was actually the signal of a massive Soviet ...

In the 1970s and ’80s, a haunting tapping sound disrupted global radio signals—traced back to a massive, secret radar in Soviet Ukraine. The Duga radar, part of an over-the-horizon missile detection ...