The first Dairy Queen restaurant opened in Joliet, Illinois, US.
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Illinois became the first US state to make it compulsory by law to wear a seatbelt.
Illinois became the 21st state to join the United States of America.
The world's most infamous clown, John Wayne Gacy, went on trial after he murdered 33 young men in Cook County, Illinois.
An F5 max rating tornado smashed through Plainfield, Illinois, killing 29 people, injuring 353, and causing $165 million in damages.
The first Mormon Pioneers left their homes in Nauvoo, Illinois, and began the long trek to the Salt Lake Valley.
