Memorial Day in the United States (2008); Independence Day in Guyana and Georgia; Mother's Day in Poland; National Sorry Day in Australia
- 1805 – Napoléon Bonaparte was crowned King of Italy at the Milan Cathedral with the Iron Crown of Lombardy.
- 1896 – The Dow Jones Industrial Average was first published by Charles Dow as a stock market index.
- 1918 – The Democratic Republic of Georgia was proclaimed.
- 1972 – Richard Nixon and Leonid Brezhnev signed the Anti-Ballistic Missile Treaty in Moscow, concluding SALT I.
- 1986 – The European Community adopted the European flag (pictured).
