1. Illinois Statehood Day: May 17 marks the anniversary of Illinois becoming the 21st state in the Union. On this day in 1818, Congress passed an act granting statehood to Illinois.

2. Birth of the skyscraper: On May 17, 1884, the world's first skyscraper was completed in Chicago. The Home Insurance Building stood 10 stories tall and was constructed with a metal frame that allowed for the use of large plate-glass windows.

3. Capone in court: On May 17, 1929, Al Capone appeared in court in Chicago to face charges of contempt of court for failing to appear in court in Philadelphia. Capone was ultimately found guilty and sentenced to six months in prison.

4. Great Flood of 1943: On May 17, 1943, heavy rains caused the worst flooding in Illinois history, with more than 70,000 people displaced and hundreds of millions of dollars in damage. The flood was caused by a combination of melting snow and heavy rainfall.

5. Barack Obama's first political campaign: On May 17, 1996, Barack Obama made his first political campaign as he ran for the Illinois State Senate. He ended up winning the primary, defeating 3 other candidates. This marked the beginning of his political career.