1. 1775 – American Revolution: The Siege of Boston begins, following the battles at Lexington and Concord.

2. 1862 – Louis Pasteur and Claude Bernard complete the first pasteurization tests.

3. 1889 – Adolf Hitler is born in Braunau am Inn, Austria-Hungary.

4. 1902 – Marie and Pierre Curie refine radium chloride.

5. 1961 – The failed Bay of Pigs invasion of Cuba comes to an end with the surrender of the last group of CIA-sponsored paramilitary invaders to the Cuban government.

6. 1972 – Apollo 16, manned by John Young, Charles Duke, and Ken Mattingly, lands on the moon.

7. 1999 – The Columbine High School massacre occurs, where two students kill 13 people and injure 24 others before committing suicide in Littleton, Colorado.

8. 2010 – The Deepwater Horizon drilling rig explodes in the Gulf of Mexico, leading to one of the largest environmental disasters in U.S. history.

9. 2013 – A powerful earthquake in Sichuan, China, kills at least 193 people and injures more than 12,000 others.

10. 2018 – Swedish electronic dance music DJ, Avicii (Tim Bergling), is found dead in Muscat, Oman. His death is later ruled a suicide.