30 June History
- 1520 - Montezuma II is murdered as Spanish conquistadors flee the Aztec capital of Tenochtilan during the night.
- 1857 - Charles Dickens reads from A Christmas Carol at St. Martin's Hall in London–his first public reading.
- 1859 - Jean Francois Gravelet aka Emile Blondin, a French daredevil, becomes the first man to walk across Niagra Falls on a tightrope.
- 1908 - A mysterious explosion, possibly the result of a meteorite, levels thousands of trees in the Tunguska region of Siberia with a force approaching twenty megatons.
- 1934 - Adolf Hitler orders the purge of his own party in the "Night of the Long Knives."
- 1936 - Margaret Mitchell's novel, Gone With the Wind, is published.
- 1948 - John Bardeen, Walter Brattain, and William Shockley demonstrate their invention, the transistor, for the first time.
- 1960 - Alfred Hitchcock's film, Psycho, opens.
- 1971 - Three Soviet cosmonauts die when their spacecreaft depressurizes during reentry.
30 June Birthdays
- 1685 - John Gay, poet and playwright (The Beggar's Opera).
- 1768 - Elizabeth Kortright, later Elizabeth Monroe, first lady to U.S. President James Monroe.
- 1911 - Czeslaw Milosz, Polish poet and critic.
- 1917 - Lena Horne, American singer.
- 1919 - Susan Hayward, actress.
- 1926 - Paul Berg, Nobel Prize-winning biochemist.
- 1932 - Mongo Beti, novelist and political writer.