1. On May 18, 1896, the Supreme Court of Mississippi upheld the constitutionality of the state's new poll tax, which aimed to restrict voting rights for black citizens. This decision further solidified the South's system of Jim Crow laws and voter suppression.

2. In 1934, a massive tornado outbreak struck Mississippi on May 18, leaving 17 dead and causing widespread destruction. This event is known as the "Tri-State Tornado Outbreak" and affected multiple states in the Southeast.

3. On May 18, 1963, civil rights leader Medgar Evers was assassinated outside of his home in Jackson, Mississippi. Evers had been working to desegregate schools and public spaces in the state, and his death was a major blow to the civil rights movement.

4. In 1980, a major eruption of Mount St. Helens in Washington State caused ash to drift as far south as Mississippi. The ashfall was reported in multiple cities, including Hattiesburg.

5. On May 18, 2001, Mississippi musician Elmore James was posthumously inducted into the Blues Foundation's Hall of Fame. James was known for his distinctive slide guitar style and is considered one of the pioneers of modern blues music.