1774 ― Priestly discovers oxygen
1789 ― U.S. Customs begins enforcing Tariff Act
1790 ― First U.S. census (population of 3,939,214)
1831 ― London Bridge officially opens
1834 ― Slavery abolished in British Empire
1876 ― Colorado becomes 38th state
1914 ― Germany declares war on Russia in WWI
1916 ― Hawaii National Park established
1950 ― Territory of Guam created
1953 ― California introduces sales tax (for education)
1955 ― First microgravity research begins
1960 ― Benin gains independence from France
1992 ― NBC's "Saturday Today" premieres