1. Missouri State Fair: The Missouri State Fair was established on August 23, 1901, in Sedalia, Missouri. The fair is held annually and is one of the largest state fairs in the United States, attracting over 300,000 visitors each year.

2. Missouri enters the Union: On August 23, 1821, Missouri became the 24th state to join the Union. It was the first state west of the Mississippi River to be admitted to the Union.

3. Harry S. Truman visits Missouri: On August 23, 1945, Harry S. Truman visited his home state of Missouri for the first time since becoming president. He made an address in Kansas City where he discussed the end of the war and the future of the United States.

4. Jesse James is killed: On August 23, 1876, outlaw Jesse James was shot and killed by Robert Ford in his home in St. Joseph, Missouri. Ford was a member of James' gang and had conspired to kill him in order to collect a reward.

5. Gateway Arch dedication: On August 23, 1961, the Gateway Arch in St. Louis, Missouri, was dedicated. The arch is a symbol of St. Louis and stands as a monument to westward expansion and American history.