1. On April 20, 1831, Chicago was incorporated as a city, with a population of just over 4,000 residents. Today, Chicago boasts a population of over 2.7 million people and is one of the largest cities in the United States.

2. On April 20, 1939, future Illinois governor Daniel Walker was born in Washington, D.C. Walker served as governor from 1973 to 1977 but later served time in prison for charges including bank fraud and perjury.

3. April 20, 1999, saw the tragic school shooting at Columbine High School in Colorado, which claimed the lives of 13 people. The tragic event spurred new discussions on gun control laws and school safety protocols, affecting schools across the United States, including in Illinois.

4. April 20, 2002, marked the opening of the Abraham Lincoln Presidential Library and Museum in Springfield, Illinois. The museum contains a vast collection of artifacts and exhibits related to the life and legacy of the 16th U.S. president.

5. On April 20, 2017, the Illinois State Senate voted to approve a bill legalizing the use and possession of recreational marijuana in the state. The bill was later signed into law on June 25, 2019, making Illinois the 11th state in the U.S. to legalize marijuana.