1. In 1947, the Illinois state legislature passed the Illinois Public Aid Code, which created a comprehensive system of public assistance for low-income families and individuals. This legislation set the foundation for the modern Illinois Department of Human Services.

2. On June 17, 1969, the Chicago Cubs played their first night game at Wrigley Field. This historic game against the Philadelphia Phillies was also the first Major League Baseball game played under lights in Chicago.

3. In 1972, the Illinois state legislature adopted a new constitution, which replaced the previous constitution that had been in place since 1870. The new constitution expanded the right to vote, established protections for the environment and individual rights, and reformed the state's court system.

4. On June 17, 1986, the Chicago Bears retired the jersey number 34 in honor of the legendary running back Walter Payton. Payton had played his entire career with the Bears, leading the team to its first Super Bowl victory in 1985.

5. In 2015, the state of Illinois legalized same-sex marriage, becoming the 16th state in the nation to do so. The legislation was passed by the state legislature and signed into law by Governor Pat Quinn, and took effect immediately. The law recognized marriages between same-sex couples performed outside of Illinois as well as those performed within the state.