An F5 max rating tornado smashed through Plainfield, Illinois, killing 29 people, injuring 353, and causing $165 million in damages.
The world's most infamous clown, John Wayne Gacy, went on trial after he murdered 33 young men in Cook County, Illinois.
John Wayne Gacy was arrested.
The FDA approved the first oral contraceptive pill called Enovid.
The first private research atomic reactor opened in Chicago, Illinois, US.
Illinois became the first US state to make it compulsory by law to wear a seatbelt.
The world's first self-sustaining nuclear chain reaction happened in Chicago Pile-1 at the University of Chicago. It was overseen by Enrico Fermi.
The first Dairy Queen restaurant opened in Joliet, Illinois, US.
Coopers Inc. started selling the world's first men's briefs in Chicago.
Paul Galvin and his brother Joseph founded Motorola as the 'Galvin Manufacturing Co.' in Chicago, Illinois.
The first Sears retail store opened in Chicago.
The Cherry Mine disaster in Illinois killed 259 miners in a coal mine fire.
Great Chicago Fire begins.
The first Mormon Pioneers left their homes in Nauvoo, Illinois, and began the long trek to the Salt Lake Valley.
Illinois became the 21st state to join the United States of America.
