1. On May 20, 1862, the Homestead Act was signed into law by President Abraham Lincoln. This act provided 160 acres of land to any person who was willing to live on and cultivate the land for at least five years. Many people from Iowa took advantage of this opportunity to own their own farms and build new lives for themselves and their families.

2. May 20, 1891, saw the founding of the Baconian Club of Des Moines, Iowa. This club was composed of a group of local doctors and scientists who met regularly to discuss the latest ideas and advancements in their respective fields. The club was named after Sir Francis Bacon, a 17th-century philosopher and scientist who was known for his contributions to the scientific method.

3. On May 20, 1916, the Iowa State Capitol building in Des Moines was officially dedicated. This impressive neoclassical structure was designed by architect John C. Cochrane and took 15 years to construct. It is considered one of the most beautiful and iconic state capitol buildings in the United States.

4. May 20, 1967, was the day that "The American Adventure" exhibit opened at Disneyland in Anaheim, California. This multimedia experience showcased the history and culture of the United States through animatronic figures and audio-visual displays, with Iowa native and famous broadcaster Walter Cronkite serving as the narrator.

5. Finally, on May 20, 2004, Iowa City resident Kurt Vonnegut received the Carl Sandburg Literary Award from the Chicago Public Library. Vonnegut was a celebrated author and essayist known for his satirical and irreverent works such as "Slaughterhouse-Five" and "Cat's Cradle," which made him a beloved figure among Iowa's literary community.