The Aon Center in Chicago is a business building that features several major headquarters. If you are lucky enough to work in the building or know someone who does, you will be able to get access to the 83 floors above ground as well as the five below ground. When looking at the Chicago skyline, you can see the Aon Center between Two Prudential Plaza and Blue Cross and Blue Shield Tower. This skyscraper was built in 1973 and measures 1,136 feet high, meaning that it can provide unique views if you are able to get to the top. The best way to enjoy the view is to visit one of the cafes inside.