1. In 1986, the Chicago Bears won the Super Bowl
On January 27, 1986, the Chicago Bears defeated the New England Patriots 46-10 in Super Bowl XX. The Bears' victory is considered one of the greatest in NFL history and is still celebrated by fans today.

2. In 1924, the first Winter Olympics were held in Chamonix, France
Though not specifically an event in Illinois history, the first Winter Olympics were held on January 27, 1924. The games included events such as skiing, speed skating, ice hockey, and figure skating, and paved the way for many future Winter Olympics.

3. In 1951, the first experimental nuclear reactor went critical at the University of Chicago
The first experimental nuclear reactor, known as the Chicago Pile-1, went critical on January 27, 1951. The reactor was designed by Enrico Fermi and his team of scientists, and was a significant step in the development of nuclear energy.

4. In 1868, the Chicago & Northwestern Railway was incorporated in Illinois
The Chicago & Northwestern Railway was incorporated on January 27, 1868 in the state of Illinois. The railroad played a significant role in the development of the Midwest, connecting Chicago to cities such as Milwaukee and Minneapolis.

5. In 2012, daily gun violence reached a peak in Chicago
On January 27, 2012, the city of Chicago experienced an alarming spike in gun violence. In just 24 hours, 10 people were killed and 40 others were injured in a series of shooting incidents throughout the city. The event underscored the ongoing issue of gun violence in Chicago and sparked a renewed debate over gun control laws in the United States.