1. In 1940, the Indianapolis 500 was held on May 18th for only the second time in its history. Wilbur Shaw won his second consecutive race, driving an Maserati car.

2. On May 18, 1954, the United States Supreme Court issued a ruling in the landmark case Brown v. Board of Education, which declared segregation in public schools unconstitutional. The case was brought by a group of African American parents in Topeka, Kansas, but had national implications and led to the desegregation of schools across the country, including in Indiana.

3. In 1979, a major tornado outbreak hit Indiana on May 18th. Dozens of tornadoes touched down across the state, killing 11 people and causing widespread damage. It remains one of the worst tornado outbreaks in Indiana's history.

4. The Indiana War Memorial was dedicated on May 18, 1960. The memorial, located in downtown Indianapolis, honors the state's veterans of World War I, World War II, the Korean War, and other conflicts. It features a museum, a library, and a 210-foot-tall tower.

5. On May 18, 1980, the eruption of Mount St. Helens in Washington State sent ash and debris into the atmosphere, causing widespread damage and killing 57 people. The effects of the eruption were felt even in Indiana, where ash fell from the sky and air travel was disrupted for several days.