1. In 1837, the city of Chicago was incorporated as a city. Prior to its incorporation, Chicago was only a small town with a population of around 4,000 people.

2. On June 21, 1864, the Battle of Jerusalem Plank Road took place during the American Civil War. Union forces were able to successfully cut off a Confederate supply line, resulting in a significant loss for the Confederate army.

3. In 1906, the Pure Food and Drug Act was signed into law by President Theodore Roosevelt. This act was designed to protect consumers by regulating the production and sale of food and drugs, and it played a significant role in the development of modern food safety practices.

4. On June 21, 1932, the World's Fair opened in Chicago. The fair, which was officially known as the Century of Progress International Exposition, celebrated the 100th anniversary of the city's incorporation and showcased many of the technological advancements of the time.

5. In 1985, the first Route 66 festival was held in Springfield, Illinois. The festival was designed to celebrate the historic Route 66 highway, which ran through several states, including Illinois, and was a significant part of American culture in the mid-20th century. Today, the festival continues to attract visitors from around the world.