1. On April 21, 1870, the first Arbor Day was celebrated in the United States in Nebraska. However, Iowa was actually the first state to officially declare Arbor Day a holiday in 1884.

2. In 1934, a massive dust storm known as Black Sunday swept through Iowa, causing widespread damage to crops and property. The storm was part of the larger Dust Bowl phenomenon that devastated much of the Great Plains during the 1930s.

3. On April 21, 1910, the Iowa State Capitol building in Des Moines officially opened its doors. The building, which stands over 275 feet tall and features a golden dome, is one of the most iconic landmarks in the state.

4. Iowa-born actress Virginia Christine, best known for her role as Mrs. Olson in the Folgers coffee commercials, was born on April 21, 1920. Christine appeared in dozens of films and TV shows during her career, including the classic film "Invasion of the Body Snatchers."

5. On April 21, 2018, the University of Iowa's Hawkeye women's gymnastics team won their 7th Big Ten Championship. The team, which had struggled with injuries throughout the season, overcame adversity to claim the title and secure a spot in the NCAA Championships.