Chicago is famous because it is home to the first skyscraper. It is one of the biggest US cities and has a lot for tourists to enjoy. Some of its fame is not enviable, for instance the Great Chicago Fire of 1871. The story is that Mrs. O'Leary's cow kicked over a lantern and started the fire that burned out 4 sq miles of Chicago.
Chicago is also famous for the St. Valentine's Day Massacre . The Sears Tower was once the tallest building in the world but even now people love to visit it, and there's plenty of culture in Chicago too.