200 East Randolph Street
Chicago, IL 60601
Rising 1136 feet (346 meters), Aon Center is one of the dominant features of Chicago's skyline and is one of the tallest buildings in the city. Originally constructed as the Standard Oil building in 1973, it broke records to become the tallest in the city, and in a span of four decades, only two others have been able to top its height. The 84-story building got its current name in 1999, when it was sold to The Blackstone Group.