In this infographic, Danielle Chenette tells the story of the unknown and mysterious “hum,” a phenomenon involving a persistent droning sound only about 2% of the population can hear in certain areas.
The most publicized area where this occurs in the United States is in Taos, N.M. But it also occurs in different countries in the world such as Bristol in England, Windsor in Ontario, Auckland in New Zealand and the Kokomo Hum. There is still no scientific explanation for the sound at this time.
For more information about this weird sound phenomenon read this.