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
Century Tower (Chicago) is listed in the National Register of Historic Places. This building has formerly been named: Century Tower (Chicago) The Century Tower Condominiums, formerly known as the Trustees System Service Building, is a historic building located at 182 West Lake Street in the Loop in Chicago, Illinois. The building was designed in 1929 and completed in 1930; at the time of its completion, it was the tallest reinforced concrete building in the world. Its original tenant and namesake was the Trustees Service System, a bank that specialized in consumer loans. Architects Thielbar and Fugard designed the building in the Art Deco