1. On April 22, 1880, William "Coin" Harvey of Buffalo, Arkansas registered a patent for a new method of refining silver. Harvey went on to become a well-known writer and political activist, advocating for monetary reform and the adoption of silver as currency.

2. The University of Arkansas opened its doors to students for the first time on April 22, 1872. The school had originally been founded as Arkansas Industrial University in 1871, but was renamed in 1899.

3. On April 22, 1913, a tornado touched down in the town of Booneville, Arkansas, causing widespread destruction and leaving dozens injured. The tornado was part of a larger outbreak that swept through the southern United States, killing more than 200 people.

4. The Arkansas Penitentiary, now known as the Cummins Unit, was established on April 22, 1902. The maximum security prison has a long and complex history, including a high-profile riot in 1974 that left 39 inmates dead.

5. On April 22, 1970, more than 20 million Americans participated in the first Earth Day, a nationwide event dedicated to raising awareness about environmental issues. Today, Earth Day is celebrated annually in more than 190 countries around the world.