The Hum is an odd low frequency droning or rumbling sound that has no definitive origins.
It's been heard around the world for decades now, but can only be heard by a small fraction of the global population.
The Hum has been reported world wide, however for some reason certain areas like Taos, New Mexico and Windsor, Ontario, have become particularly known for their localized Hum phenomena, often referred to as the "Taos Hum" or "Windsor Hum.
Explanations for it's source have ranged from Power Plants, High voltage power lines, cell towers, radio waves tinnitus or even paranormal activity like aliens or psychic/spiritual powers
Though to this day it's true source is unknown...
Locations the Hum has been reported in