Taos, New Mexico isn't the only place where a bizarre ambient hum is heard, but it's probably the most famous spot for the mysterious droning, so much that it's mentioned in travel guidebooks about the area. The Taos Hum reportedly is heard by only 2 percent of the local population and been described as a sound similar to the low rumble of a diesel truck's engine [source: Eisenberg].
People who noticed it are bothered to varying degrees, with some experiencing a mild feeling of irritation, while others report sleep disturbances, dizziness and nosebleeds. Conspiracy theorists suggest that it's caused by some sort of secret military communications system used to contact submarines, or a clandestine weapons testing program.
However, scientists think it may be caused by low frequency waves that originate in the atmosphere or else by vibrations from deep within Earth. A third hypothesis is that some people are extraordinarily sensitive to certain electromagnetic frequencies, and that the hum is caused by devices such as cell phones. But again, nobody really knows for sure [sources: Strange Sounds, Eisenberg].
Author's Note: 10 Unidentified Sounds That Scientists Are Seriously Looking Into
I can't say that I've experienced any of the unexplained sounds described in this article—I was in Taos once during the mid-1980s, for example, and the only odd phenomenon that I noticed was a local artist who wore cowboy boots that he'd apparently spray-painted fluorescent orange. When I started working in downtown Baltimore a few years later, I remember that on one of my first afternoons on the job, I was startled by the loud, eerie wail of a siren. No one else in the office seemed to notice it. I eventually discovered that it was the weekly test of an emergency alert system, and sounded at 1 p.m. each Monday. In time, I became accustomed to it as well.
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