You are a British intelligence agent. You're in North Korea. Because you're of Korean descent, and speak fluent Korean, you blend in, but your papers are forged, your identity is false, and you are as alone as it is possible for any human being to be.
It rains constantly. You are always afraid. You know that if anyone ever even suspects you, you will simply vanish. You will be taken to a "facility" somewhere, you will be tortured for weeks or months, and eventually, you will be shot. The British government will deny any knowledge of your existence. You are a nonperson, and you are in constant, desperate danger.
Sometimes you wonder if the constant fear will drive you insane. You have only one link with your home. Every night, at 3 in the morning, you awaken. You turn on your portable shortwave radio, using an earphone to insure that nobody can hear. You take out a notepad and a pencil, and turn the radio on. And through the static, and the interference, and the maddening distortions caused by the atmosphere -- there is a storm over the Sea of China tonight -- you strain to make it out. A weirdly disembodied child's voice, repeating what sound like meaningless numbers, endlessly.
You write them down. You click off the radio. You wonder if you're going mad. And you remember that one night, those numbers will lead you to a field, a waiting SAS insertion team, a submarine, and home. It's all you've got.
Okay, that part, obviously, is fiction. But I just learned about something absolutely fascinating -- numbers stations. These are shortwave stations around the world that broadcast ... numbers. Human, or computer-generated voices, that simply read out strings of numbers.
These stations, although it has never been proven, are operated by government espionage agencies all over the world. They're a simple, foolproof way to send coded messages to spies around the world.
And the sound of the reading itself is absolutely eerie. Listen: