Aon Center

The Aon Center is a modern supertall skyscraper in the Chicago Loop, Chicago, Illinois, United States, designed by architect firms Edward Durell Stone and The Perkins and Will partnership, and completed in 1974 as the Standard Oil Building. With 83 floors and a height of 1,136 feet, it is the fourth-tallest building in Chicago, surpassed in height by Willis Tower, Trump International Hotel and Tower, and St Regis Chicago.

The building is managed by Jones Lang LaSalle, which is also headquartered in the building. Aon Center also houses the headquarters of Aon and one of Kraft Heinz's two headquarters, and the former world headquarters of Amoco prior to its acquisition by BP.The building was briefly the tallest in Chicago, but was soon surpassed by the Sears Tower. However, the Aon Building was the fourth-tallest completed building in the world at the time of its completion.