5. An American bomber covertly stationed in Canada dropped and detonated a nuclear bomb over Quebec
On November 10, 1950, a USAF B-50 bomber suffered critical engine malfunctions during a training flight as it returned from Labrador, Canada, to its home base at Davis-Montham Air Force Base in Tuscon, Arizona. Secretly deployed in Canada, the aircraft lost power in two of its engines soon after take-off. Fearing a devastating outcome in the event of a crash, the bomber’s crew armed their payload: a nuclear weapon containing high explosives and nuclear material but no plutonium core. Setting the bomb to self-destruct at 2,500 feet the crew jettisoned the nuclear device at 10,500 feet while over the 12 mile wide St. Lawrence River, near St. Alexandre-de-Kamouraska, Quebec, Canada.
Whilst the incident resulted in zero known casualties, with the B-50 successfully continuing its flight to a safe destination and the bomb detonating at the chosen altitude, the aerial explosion shook and terrified local Canadian residents, reportedly rattling the windows of houses across a 25 mile area. Additionally, the detonation scattered nearly 100lbs of uranium used in the weapon over the river and local area. The Department of Defense has never confirmed the successful recovery of the weapon or its components from the river.