DC Comics released Flash Comics Issue 1, featuring Flash Gordon.
US President Franklin D. Roosevelt received a letter from Albert Einstein detailing the possibility of atomic weapons.
The NBC broadcasted the first live American football game.
Finnish long-distance runner Taisto Mäki broke the 10,000-meter world record in 29:52:06.
The Vought-Sikorsky VS-300 became the first successful helicopter to fly.
Germany invaded Poland in the free city of Danzig, which started World War II.
The world's first jet-powered aircraft, the Heinkel He 178, completed its first flight.
Legend Frank Sinatra recorded his debut single with the Harry James band.