
| Isabella of Castile, patron of Columbus | |
| Immanuel Kant, philosopher (Critique of Pure Reason) | |
| Vladimir Ilich Lenin, Bolshevik | |
| J. Robert Oppenheimer, physicist, nuclear pioneer. | |
| Yehudi Menuhin, violinist | |
| Lyrid meteor shower, radiant in Hercules | |
| Earth Day | |
| Pedro Alvarez Cabral discovers Brazil | |
| Henry VIII ascends to throne of England | |
| Spain & Portugal divide eastern hemisphere in Treaty of Saragossa | |
| US Congress authorized 'In God We Trust' on coinage | |
| Oklahoma land rush officially started; some were Sooner | |
By Scott Labrecque version 9.4.0.0