1. In 1837, the city of Chicago officially became a city after a referendum vote approved the incorporation of the city.
2. In 1861, the Civil War Camp Douglas was established in Chicago, Illinois. It became one of the largest Union training camps and prisoner-of-war camps during the war.
3. In 1973, the Illinois Supreme Court ruled that the death penalty was unconstitutional, making Illinois the first state to abolish the death penalty since it was reinstated by the United States in 1976.
4. In 1982, Chicago native Harold Washington became the first African American to win the Democratic nomination for mayor of Chicago, eventually going on to win the general election and becoming the city's first black mayor.
5. In 2019, the Chicago Teachers Union went on strike for the first time in seven years, demanding better pay, smaller class sizes, and more support staff in schools. The strike lasted for 11 days and ended with the union reaching a tentative agreement with the city.