The co-pilot of Germanwings Flight 9525 deliberately crashed the aircraft, an Airbus A320, in a mass murder–suicide in the French Alps, killing all 150 people on board.
One day after making a plea to Salvadoran soldiers to stop carrying out the government's repression, Archbishop Óscar Romero was assassinated while celebrating Mass in San Salvador.
Members of the German National Movement in Liechtenstein attempted to overthrow the government and provoke Liechtenstein's annexation into Nazi Germany.
The Tydings–McDuffie Act came into effect, which provided for self-government of the Philippines and for Filipino independence from the United States after a period of ten years.
Irish War of Independence: In Belfast, two men wearing police uniforms broke into a house and murdered a Catholic family in what was believed to be a reprisal for the deaths of two policemen the day before.
The inaugural Women's Olympiad (cover pictured), the first international women's sports event, opened at the International Sporting Club of Monaco in Monte Carlo.