April 3: German ships set out for the invasion of Norway.

April 5: Neville Chamberlain, Prime Minister of the United Kingdom, in what proves to be a tragic misjudgment, declares in a major public speech that Hitler has "missed the bus".

April 7: Booker T. Washington becomes the first African American to be depicted on a United States postage stamp.

April 9: Germany invades the neutral countries of Denmark and Norway in Operation Weserübung. The British campaign in Norway is simultaneously commenced.

April 12: The Faroe Islands are occupied by British troops, following the taking over of Denmark by Nazi Germany. This action is taken to avert a possible German occupation of the islands with serious consequences for the course of the Battle of the Atlantic. - Opening day at Jamaica Race Course features the use of parimutuel betting equipment, a departure from bookmaking heretofore used exclusively throughout New York. Other tracks in the state follow suit later in 1940.

April 13: The New York Rangers win the 1940 Stanley Cup Finals in ice hockey. It will be another 54 years before their next win.

April 21: Take It or Leave It makes its debut on CBS Radio, with Bob Hawk as host.

April 23: The Rhythm Club fire at a dance hall in Natchez, Mississippi, kills 198. (source: Wikipedia)