1. In 1812, Native American forces led by Chief Black Hawk launched an attack on a group of Illinois settlers in the Battle of the Pecatonica. The settlers were ultimately able to fend off the attack, but the battle marked the beginning of the Black Hawk War.

2. On June 18, 1858, Abraham Lincoln delivered his famous "House Divided" speech in Springfield, Illinois, in which he warned against the dangers of a nation divided over the issue of slavery. The speech is widely considered to be one of the most important in American history.

3. In 1910, the University of Illinois at Urbana-Champaign dedicated its new football stadium, Memorial Stadium. The stadium has since become an iconic symbol of the university and a popular destination for sports fans.

4. On June 18, 1942, the United States Navy began construction on a new naval base in Great Lakes, Illinois. The base, known as Naval Station Great Lakes, became one of the largest military installations in the country and remains an important training center for Navy recruits to this day.

5. In 1987, a massive tornado swept through the town of Plainfield, Illinois, causing extensive damage and claiming the lives of 29 people. The tornado was one of the most destructive in Illinois history and served as a powerful reminder of the dangers of extreme weather events.