1876 – The first ever National League baseball game is played in Philadelphia.
1906 – The 1906 Summer Olympics, also known as the Interclated Games, not now recognized as part of the official Olympic Games, open in Athens.
1930 – The United Kingdom, Japan and the United States sign the London Naval Treaty regulating submarine warfare and limiting shipbuilding.
1945 – After learning that Soviet forces have taken Eberswalde without a fight, Adolf Hitler admits defeat in his underground bunker and states that suicide is his only recourse.
1970 – The first Earth Day is celebrated.
