Aon Center (Chicago) the world headquarters of Aon and Amoco. Aon's US operations are still headquartered here. The building is also the co-headquarters of Kraft Heinz. The Standard Oil Building was constructed as the new headquarters of the Standard Oil Company of Indiana, which had previously been housed at South Michigan Avenue and East 9th Street. When it was completed in 1973, it was the tallest building in Chicago and the fourth-tallest in the world, earning it the nickname "Big Stan". (A year later, the Sears Tower took the title as Chicago's and world's tallest.) The building employs a tubular steel-framed structural system
Equitable Building (Chicago) Equitable Building (Chicago) 401 North Michigan is a 35-story skyscraper in the Streeterville area of Chicago, built in 1965 at 401 North Michigan Avenue, along the north bank of the Chicago River. Along with the Tribune Tower and Wrigley Building, it forms the southern gateway to Chicago's famous Magnificent Mile. The building was built atop the site of a cabin belonging to Chicago's first permanent resident, Jean Baptiste Pointe du Sable. In reference to du Sable, the large plaza adjacent to the building has been named Pioneer Court. 401 North Michigan occupies a site with several aspects of historical significance,