April 2, 1917 US President Woodrow Wilson delivers his message before Congress and recommends that war be declared against the German government.

April 3, 1933 Royal Air Force Lieutenant David McIntyre and the Scottish Marquess of Clydesdale, flying two open-cockpit Westland aircraft, complete the first overflight and aerial photographic survey of Mt Everest.

April 4, 1949 The 12-nation North Atlantic Treaty Organization (NATO) pact is si