UVB-76 / The Buzzer (Cold War Era - Present)

UVB-76, nicknamed "The Buzzer," is a shortwave radio station that has broadcast a continuous, monotonous buzzing tone since the Cold War. Occasionally, it transmits cryptic voice messages reading strings of numbers and names. Believed to be a Russian military signal, its precise purpose remains classified, fueling theories about dead hand triggers, espionage communication, or military mobilization, making it an enduring Cold War mystery.