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
Sears, Roebuck and Company Complex a modillioned cornice. It housed water tanks for firefighting on the upper levels, as well as offices and secretarial training facilities. It also housed the early broadcast facilities for WLS-AM. In 2015, it was refurbished and reopened to the public as the "John D. and Alexandra C. Nichols Tower". It now houses non-profit groups and offices, including a classroom on the 12th floor for the School of the Art Institute of Chicago. The Sears Roebuck plaque is still visible on top of the building. The Sears, Roebuck and Company Administration Building is a broad five-story masonry building, occupying about 3/4