This morning, I came across an article on Yahoo News and remembered seeing this thread . . .
Mysterious Hum Driving People Around the World Crazy
http://news.yahoo.com/mysterious-hum-driving-people-around-world-crazy-115259328.htmlexcerpts from the article:
It's known as the Hum, a steady, droning sound that's heard in places as disparate as Taos, N.M.; Bristol, England; and Largs, Scotland.
Reports started trickling in during the 1950s from people who had never heard anything unusual before; suddenly, they were bedeviled by an annoying, low-frequency humming, throbbing or rumbling sound.
Most of the people who hear the Hum (sometimes referred to as "hearers" or "hummers") describe the sound as similar to a diesel engine idling nearby. And the Hum has driven virtually every one of them to the point of despair.
Most researchers investigating the Hum express some confidence that the phenomenon is real, and not the result of mass hysteria or hearers' hypochondria (or extraterrestrials beaming signals to Earth from their spaceships).