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
Chase Tower (Chicago) Chase Tower (Chicago) Chase Tower, located in the Chicago Loop area of Chicago, in the U.S. state of Illinois at 10 South Dearborn Street, is a 60-story skyscraper completed in 1969. At 869 feet (259 m) tall, it is the eleventh-tallest building in Chicago, the tallest building inside the Chicago 'L' Loop elevated tracks, and the 40th-tallest in the United States. Chase Bank has its U.S. and Canada commercial and retail banking headquarters here. The building is also the headquarters of Exelon. The building and its plaza (known as Exelon Plaza) occupy the entire block bounded by Clark, Dearborn, Madison,