- A US Surgeon General's report came out stating that nicotine was addictive just like cocaine. (1988) The addictive properties of nicotine were still being debated in the 1980s, and the report was shocking to many.
- The Cultural Revolution began in China. (1966) Mao Zedong's government published the May 16 Notification, which stated that "The Great Cultural Revolution" had been launched, with warnings against "revisionist" thinking. The notification was originally only available to higher ranking party members, but was widely circulated within a year, leading to mass rallies where books and things representing the old society were destroyed.
- The first Academy Awards ceremony was held. (1929) The winners had been announced three months before in trade magazines, so the event didn't have the element of suspense that is now does. Tickets to the event cost $5 US Dollars (USD), and the silent film Wings took home the Best Picture Oscar.
- Andrew Johnson was acquitted of "high crimes and misdemeanors". (1868) The deeply unpopular Johnson had been charged with 11 articles of impeachment. The Senate was one vote short of convicting Johnson, and he was acquitted of all charges.
- Edgar Allen Poe married his 13-year-old cousin, Virginia. (1836) The two were devoted to each other until she died from tuberculosis some ten years later. Virginia served as the inspiration for some of Poe's most famous poems, including Annabel Lee, Ulalume, and Lenore.
- Root beer is said to have been invented. (1866) One of the most popular forms of root beer is said to have been invented by Charles Elmer Hines on his honeymoon on this day. Though similar beverages were already made throughout the United States, Hines' version was the first one to make it big.
- Louis XVI and Marie Antoinette met after being married for almost a month. (1770) The two had been married by proxy on 19 April, but they met each other in France for the first time on this day when Antoinette's guardians handed her over to Louis.
- The Sedition Act of 1818 was passed. (1918) The act made it illegal to criticize the United States government, flag, or armed forces in times of war, with a prison sentence a possible punishment. The act was repealed two years later.
- SpaghettiOs® hit the market. (1965) The canned spaghetti product was intended to be a more "kid-friendly" option because of the round "o" shape. A lot of research went into determining the perfect SpaghettiOs® shape, and rejected designs included stars, astronauts, sports shapes, and cowboy shapes.
- The first woman summited Mount Everest. (1975) Japanese mountain climber Junko Tabei was the first woman as well as the first Japanese person to reach the top of the mountain. By 1992, she became the first woman to climb the Seven Summits, the tallest mountain on each of the seven continents.