1. Missouri was admitted to the Union on August 10, 1821, as the 24th state in the United States. However, on December 31, 1864, the state held its first general election under the newly adopted state constitution.

2. On December 31, 1967, the famous Gateway Arch in St. Louis was completed. It stands at 630 feet tall and is the tallest man-made monument in the United States.

3. In 1995, the Kansas City Chiefs won their first AFC West title since 1971 on December 31. They went on to the playoffs that year and advanced to the AFC Championship Game.

4. On December 31, 1905, the first conference on conservation was held in Missouri. The conference brought together people concerned about the natural resources of the state and was a significant event in the conservation movement.

5. December 31, 1978, marked the first day of operation for a new light rail system in St. Louis called the MetroLink. The system now spans 46 miles and serves both Missouri and Illinois.