Can you hear the Hum? The mystery noise that says a lot about modern life

The insistent low-frequency sound has been heard from Bristol to Swansea and ascribed to everything from horny fish to 5G - but the enigma itself is telling

Maybe you hear it. A low frequency hum, almost a vibration, just on the threshold of human hearing. It's not particularly loud. In fact, you might not have even noticed it yet - but once you do, you can't stop hearing it. It sounds like a truck, idling on the street in front your house. Or the atmospheric din of an airplane flying overhead, that never gets further away. You can hear it when you're outside, but it seems louder indoors, and particularly at night, when you're lying in bed. Maybe it keeps you awake. Maybe it causes you headaches, dizziness, even nosebleeds.

If you do hear it, you're among the roughly 4% of the world's population affected by the Hum", a frequently reported but little understood global phenomenon. The earliest reliable reports of the Hum date from the UK in the mid-1970s, most notably from Bristol, when letters began appearing in the Bristol Evening Post about a low rumble heard by dozens of residents throughout the city. What began as an irritating if innocuous noise eventually drove many who heard it to distraction, and was said to be linked to two suicides. A prevailing theory was that the Bristol Hum originated from large industrial fans used at a warehouse in nearby Avonmouth. But according to some Bristolians the Hum persists to this day, despite the warehouse having long been decommissioned.