On This Day In Canadian History.... 

1956 - A Royal Canadian Air Force CF-100 fighter jet crashes into the Grey Nuns' Home for the Aged in the Ottawa suburb of Orleans, killing 15 people, including 11 nuns.

At 10:37 p.m. two CF-100s were launched from their base at RCAF Station Uplands (located south of Ottawa) to identify an unknown aircraft heading towards Montréal. The plane was identified as a RCAF North Star flying from Resolute Bay to Dorval Airport. The two planes climbed to 33,000 feet to practice interception techniques and burn off excess fuel before returning to base.

One of the aircraft returned to base, but the other remained airborne longer to burn off more excess fuel. However, something malfunctioned on the plane. One story is that the oxygen masks of the two crewmen malfunctioned and the men lost consciousness, though the cause has never been officially determined. The plane descended at a speed of nearly 680mph and crashed into the Villa St. Louis.