The Windsor Hum is a weird thing — a low-frequency buzzing that drives some people in Windsor, Ontario crazy and, yet, doesn’t seem to be heard by the Americans who live closest to its source, an island crowded with industrial facilities. As part of a new feature exploring environmental mysteries, Kim Tingley looks at how grantees of the Canadian government are attempting to identify the exact cause of the Windsor Hum, and how an American company is getting away with banning them from the island.