1. George Dunne is Born: On December 20, 1908, George W. Dunne was born in Oak Park, Illinois. He went on to become the longest-serving Cook County Board President in history, serving for 21 years from 1969 to 1990.

2. Cook County Clerk Building Opens: The Cook County Clerk Building, which houses the Cook County Clerk's office, opened its doors on December 20, 1911. The building was designed by architect Charles W. Kallal and is located at 118 North Clark Street in Chicago.

3. First Commercial Radio Broadcasting License Issued: On December 20, 1921, the first commercial radio broadcasting license in the United States was issued to Chicago radio station 8MK (now WWJ) by the federal government. The station was owned by the Detroit News and operated out of the Detroit News Building.

4. Illinois National Guard Activated for Korean War: On December 20, 1950, the Illinois National Guard was activated for service in the Korean War. The 33rd Infantry Division, headquartered in Chicago, was sent to Japan for training and then deployed to Korea in April 1951.

5. President Obama's Election Certificate Signed: On December 20, 2012, the Illinois State Board of Elections signed the electoral college certificate for the 2012 Presidential Election, which certified Barack Obama's victory in Illinois. Obama, who was born in Hawaii but represented Illinois in the U.S. Senate, won Illinois with 57.6% of the vote.