- 1770 British explorer Captain James Cook first sights Australia
- 1775 American Revolution begins - Lexington Common, shot "heard round the world"
- 1909 Joan of Arc receives beatification by the Roman Catholic Church
- 1995 Oklahoma City bombing - a truck bomb at Alfred P. Murrah Federal Building kills 168 & injures 500
- 2011 Fidel Castro resigns from the Communist Party of Cuba's central committee after 45 years of holding the title.
Bicycle Day - Swiss chemist Dr. Albert Hofmann deliberately takes LSD for the first time.
On April 19, 1943