1. In 1953, the deadliest tornado in Missouri history struck the city of Sikeston, killing 22 people and injuring over 200 others.

2. On May 9, 1961, James "Cool Papa" Bell, a Hall of Fame baseball player who spent most of his career with the Negro Leagues, was inducted into the St. Louis Walk of Fame.

3. The Missouri General Assembly passed the first law in the United States prohibiting the sale of margarine on May 9, 1895. This law remained in effect until 1963.

4. In 1914, St. Louis hosted the World's Fair, officially known as the Louisiana Purchase Exposition. The fair opened on April 30, but May 9 was designated as "Missouri Day" and featured a parade, speeches, and other celebrations.

5. On May 9, 1950, Harry S. Truman, the 33rd President of the United States and a native of Missouri, announced that he had authorized the use of atomic weapons against North Korea during the Korean War. This decision marked the first time that nuclear weapons had been used in warfare.