1965 – U.S. president Lyndon B. Johnson signs the Social Security Act of 1965 into law, establishing Medicare and Medicaid.

1958 – U.S. President Dwight D. Eisenhower signs into law the National Aeronautics and Space Act, which creates the National Aeronautics and Space Administration (NASA).

1921 – Adolf Hitler becomes leader of the National Socialist German Workers' Party.

1940 – The animated short A Wild Hare is released, introducing the character of Bugs Bunny.

1921 – Researchers at the University of Toronto, led by biochemist Frederick Banting, prove that the hormone insulin regulates blood sugar.

1890 – Vincent van Gogh shoots himself and dies two days later.

1866 – The first permanent transatlantic telegraph cable is successfully completed, stretching from Valentia Island, Ireland, to Heart's Content, Newfoundland.

1965 – Bob Dylan goes electric at the Newport Folk Festival, signaling a major change in folk and rock music.

1974 – Watergate scandal: The United States Supreme Court unanimously ruled that President Richard Nixon did not have the authority to withhold subpoenaed White House tapes and they order him to surrender the tapes to the Watergate special prosecutor.

1487 – Citizens of Leeuwarden, Netherlands, strike against a ban on foreign beer.

 Red_Dragon wrote:

1962 – Telstar relays the first publicly transmitted, live trans-Atlantic television program, featuring Walter Cronkite.

2024 – US President Joe Biden announces he will no longer seek a second term and withdraws from the 2024 election.

1969 – Apollo program: At 02:56 UTC, astronaut Neil Armstrong becomes the first person to walk on the Moon, followed 19 minutes later by Edwin "Buzz" Aldrin.

1960 – Sirimavo Bandaranaike is sworn in as prime minister of Ceylon, becoming the world's first democratically elected female head of government.

1925 – Scopes Trial: In Dayton, Tennessee, high school biology teacher John T. Scopes is found guilty of teaching human evolution in class and fined $100.

1977 – The Central Intelligence Agency releases documents under the Freedom of Information Act revealing it had engaged in mind-control experiments.

1976 – The American Viking 1 lander successfully lands on Mars.

1969 – Apollo program: Apollo 11's crew successfully makes the first human landing on the Moon in the Sea of Tranquility. Americans Neil Armstrong and Buzz Aldrin become the first humans to walk on the Moon six and a half hours later.

1977 – The world's first Global Positioning System (GPS) signal was transmitted from Navigation Technology Satellite 2 (NTS-2) and received at Rockwell Collins in Cedar Rapids, Iowa, at 12:41 a.m. Eastern time (ET).