1. 1801: Tsar Paul I of Russia was assassinated in his bedroom at St. Michael’s Castle in Saint Petersburg.

2. 1839: The initials “O.K.” were first published in The Boston Morning Post, originating from the misspelling of “all correct” as “oll korrect.”

3. 1903: The Wright brothers obtained an airplane patent, which they used to sue other aviators for patent infringement.

4. 1919: Benito Mussolini founded the Fascist Party in Italy, which would later lead to his rise to power as dictator.

5. 1933: The German Reichstag passed the Enabling Act, granting Adolf Hitler dictatorial powers and effectively establishing the legal basis for his dictatorship.

6. 1956: Pakistan became the first Islamic republic in the world after adopting its first constitution.

7. 1983: President Ronald Reagan proposed the Strategic Defense Initiative (SDI), a missile defense system intended to protect the United States from nuclear attacks.

8. 1994: Aeroflot Flight 593 crashed in Siberia, Russia, killing all 75 people on board. The crash was caused by the captain’s 16-year-old son accidentally disengaging the autopilot while playing with the controls.

9. 2001: The Russian space station Mir was deorbited and re-entered the Earth’s atmosphere, breaking apart and falling into the South Pacific Ocean.

10. 2010: President Barack Obama signed the Affordable Care Act (ACA) into law, also known as Obamacare, which aimed to increase the quality and affordability of health insurance in the United States.