Aon Center

The Aon Center (200 East Randolph Street, formerly Amoco Building) is a modern supertall skyscraper located in the Northeast corner of the Chicago Loop, Chicago, Illinois, United States. It was designed by a partnership between architecture firms Edward Durell Stone and Perkins and Will and was completed in 1973 as the Standard Oil Building (nicknamed "Big Stan"). With 83 floors and a height of 1,136 feet (346 m), it is the fourth-tallest building in Chicago, surpassed in height by the Willis Tower, Trump International Hotel and Tower, and St. Regis Chicago. The building is managed by JLL, which is also headquartered in the building. Aon Center houses the headquarters of Aon, Blue Cross Blue Shield Association, and Kraft Heinz (BCBS and Kraft Heinz each have a second headquarters, located in Washington D.C. and Pittsburgh respectively); the building formerly served as the world headquarters of Amoco prior to its merger into BP. The building was briefly the tallest completed building in Chicago, but was soon surpassed by the Sears Tower. It was the fourth-tallest building in the world at the time of its completion.

Building data from Wikidata (CC0); heights normalised. Summary from Wikipedia (CC BY-SA).