Illinois became the 21st state to join the United States of America.
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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 FDA approved the first oral contraceptive pill called Enovid.
Great Chicago Fire begins.
John Wayne Gacy was arrested.
Paul Galvin and his brother Joseph founded Motorola as the 'Galvin Manufacturing Co.' in Chicago, Illinois.
