The world’s most infamous clown, John Wayne Gacy, went on trial after he murdered 33 young men in Cook County, Illinois.
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Illinois became the 21st state to join the United States of America.
Prolific killer John Wayne Gacy was given the death sentence for the murder of 33 young men and boys.
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 private research atomic reactor opened in Chicago, Illinois, US.