The Polish Constitution Day Parade in Chicago is the largest Polish parade outside of Poland, and celebrates the anniversary of the ratification of the Polish Constitution of May 3, 1791, which historian Norman Davies calls "the first constitution of its kind in Europe". It is the second in the world only to the United States Constitution.

John Wayne Gacy was an American serial killer and sex offender who raped, tortured and murdered at least 33 young men and boys in Norwood Park Township, near Chicago, Illinois. He became known as the Killer Clown due to his public performances as a clown prior to the discovery of his crimes.