1. On August 12, 1875, Missouri's first official state fair opened in Sedalia. It was a huge success, with over 30,000 attendees and exhibits ranging from livestock to agricultural machinery.

2. August 12, 1937 marked the opening of the Mark Twain Dam and Reservoir in Monroe County, Missouri. The dam, located on the Salt River, was built to prevent floods and provide hydroelectric power to the surrounding areas.

3. In 1947, Mizzou quarterback Don Faurot introduced the split-T formation, revolutionizing football strategy. The Tigers went on to win the Big Seven conference that year, and the split-T formation spread throughout the country.

4. On August 12, 1950, St. Louis Browns pitcher Satchel Paige became the first African American to pitch in a major league game in the state of Missouri. Paige was 44 years old at the time, and went on to pitch for several more years.

5. Missouri's first tornado warning system was activated on August 12, 1977 in St. Louis. The system, developed by the National Oceanic and Atmospheric Administration (NOAA), consisted of sirens placed throughout the city to warn residents of approaching tornadoes.