- The first spam e-mail was sent. (1978) The first spam message was sent out by a marketing representative from Digital Equipment Corporation to every west coast address on the ARPANET, the predecessor to the Internet.
- The Sears Tower became the world's tallest building. (1973) Officially known as the Willis Tower, the Sears Tower was the tallest building in the world for almost 25 years, before being surpassed by Taipei 101. It also has the highest restrooms in the Western Hemisphere.
- West Virginia enacted the first state sales tax. (1921) Although the laws for the first sales tax went on the book on this day, the state hadn't set up any process for charging or collecting the tax, so it wasn't implemented regularly until more than ten years later.
- Joseph Fletcher landed on the North Pole. (1952) Others — notably Robert Peary and Frederick Cook — had claimed to reach the North Pole before, but it's unknown whether they actually reached the exact North Pole or just got close. Fletcher was the first person to definitively, demonstrably reach the exact North Pole.
- Birmingham police officers used dogs and firehoses on civil rights protesters. (1963) The violence made the front page of the New York Times and put the national spotlight on the Civil Rights Movement.
- The Fantasticks opened, starting a record run. (1960) The show opened in Greenwich Village on this day and ran until 2003, making it the world's longest-running musical.
- Congressional hearings on General MacArthur's dismissal began. (1951) MacArthur had been relieved of his command in Asia in a controversial decision by President Truman. The hearings were extremely political, with MacArthur openly criticizing Truman's "timidity" and played a part in setting the tone for future US military involvement in Asia.
- The Kentucky Derby was nationally televised for the first time. (1952) The Derby had been popular since it was started by Meriwether Lewis Clark, the grandson of the famous explorer Meriweather Lewis, and became even more so after it was televised as part of an overall modernization of the event.
- Gone With the Wind won the Pulitzer prize. (1937) The book had taken the author, Margaret Mitchell, over seven years to write, and sold over 30 million copies. It was the only book Mitchell ever published.
- Machiavelli was born. (1469) Considered one of the founders of modern politics, Niccolo Machiavelli's The Prince is considered must-read material for politicians and business people.