For the past nine years, residents of Windsor city, situated on the Canadian side of the US-Canada border just across Detroit river, have been complaining of a mysterious and persistent low-frequency humming noise. It comes and goes at random intervals, sometimes lasting hours and other times droning on for days. Those who can hear it—for not everyone can—compares the uncomfortable hum to an idling diesel engine or a pulsating subwoofer. Others say it sounds like a continuous distant thunder. Among those affected by the noise, some state the hum causes nausea and headache. Some have trouble sleeping. And yet for some, the hum is physically manifested by rattling windows and paintings knocking off the walls.