Besides jumping off the Golden Gate Bridge, one of my other unquenchable fascinations is number stations. Why? They’re terribly creepy. Then you learn they’re for honest to god spies.

If you’re not familiar with number stations, they’re shortwave radio stations that regularly broadcast literally cryptic sequences of numbers or letters. Triangulation indicates that some of these stations are typically located on air force bases and other military installations around the world. The number sequences are believed to be one-time-pad messages sending instructions to clandestine agents somewhere in the world. By using shortwave, not only can you broadcast halfway around the world, but building a receiver in-situ is very easy.

When I listen to recordings of these stations, with all the pops, whistles, distortions, and the mechanized voice repeating cryptic sequences I get unsettled. I don’t know why. It’s just bizarre.