1. Missouri became the 24th state in the United States on April 12, 1820, after being admitted to the Union with the Missouri Compromise. The compromise, which allowed Missouri to enter the Union as a slave state while Maine was admitted as a free state, helped to temporarily resolve the contentious debate over slavery in the United States.

2. On April 12, 1861, the first shot of the Civil War was fired at the Battle of Fort Sumter in South Carolina. Missouri, like many other states at the time, was deeply divided over the issue of secession and its citizens fought on both sides of the conflict.

3. The Great St. Louis Tornado struck on April 12, 1927, killing 79 people and causing significant damage to the city. The tornado remains one of the deadliest in U.S. history and is the third-deadliest tornado in Missouri history.

4. The first professional baseball game played under the lights was held on April 12, 1930 at Sportsman's Park in St. Louis. The game featured the St. Louis Cardinals and the Philadelphia Phillies and was attended by over 20,000 fans.

5. On April 12, 1954, Bill Veeck, the owner of the St. Louis Browns, sent Eddie Gaedel to bat in a game against the Detroit Tigers. Gaedel, who was just 3'7" tall, walked on four pitches in his only major league plate appearance. Gaedel's appearance remains one of the most unusual events in baseball history.