- World War I begins: Austria declares war on Serbia; Germany on Russia and France; Britain on Germany.
- Austrian Archduke Francis Ferdinand and wife Sophie assassinated in Sarajevo by Serbian nationalist Gavrilo Princip.
- Panama Canal is officially opened after 10 years of construction.
President: Woodrow Wilson
Vice President: Thomas R. Marshall
|Federal spending: $0.73 billion
Consumer Price Index: 10
Cost of a first-class stamp: $0.02
Boston Braves d. Philadelphia A's (4-0)
Toronto Blueshirts (NHA )
Women: Dorothea Chambers d. E. Larcombe (7-5 6-4)
Men: Norman Brookes d. T. Wilding (6-4 6-4 7-5)
Kentucky Derby Champion
NCAA Football Champions
- In his second big-screen appearance, Charlie Chaplin plays the Little Tramp, his most famous character.
- Edgar Rice Burroughs' Tarzan of the Apes published.
- Winsor McCay unleashes Gertie the Dinosaur, the first animated cartoon.
- Nobel Prizes in Science
- Chemistry: Theodore W. Richards (US), for determining atomic weight of many chemical elements
- Physics:Max von Laue (Germany), for discovery of diffraction of Roentgen rays passing through crystals
- Physiology or Medicine: Robert Bárány (Austria), for work on physiology and pathology of the vestibular system
- George Washington Carver begins experimenting with peanuts as a new cash crop for Southern farmers.
- The last known passenger pigeon dies in the Cincinnati Zoo.