1. On May 5, 1866, the first train arrived in Sedalia, Missouri. This marked the beginning of the Missouri Pacific Railroad and helped to spur economic growth in the area.

2. May 5, 1892 saw the birth of Harold Eugene Edgerton in Fremont, Nebraska. He was later to become a professor at the Massachusetts Institute of Technology (MIT) and the inventor of the electronic flash, which revolutionized photography.

3. In 1923, on May 5, the St. Louis Cardinals played their first night game at Sportsman's Park, marking a major milestone in the history of baseball.

4. On May 5, 1981, the Kansas City Royals set a Major League Baseball record by winning their first seven extra-inning games of the season.

5. Finally, on May 5, 2005, the Missouri Supreme Court overturned the state's caps on non-economic damages in medical malpractice cases, ruling that such caps violated the right to a trial by jury. This decision had far-reaching implications for medical malpractice law in Missouri as well as across the United States.