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
Chicago Water Tower Louisville Water Tower in Louisville, Kentucky. The Chicago Water Tower now serves as a Chicago Office of Tourism art gallery known as the City Gallery in the Historic Water Tower. It features the work of local photographers and artists, and filmmakers. The tower, built in 1869 by architect William W. Boyington from yellowing Lemont limestone, is 182 feet (55 m) tall. Inside was a 138-foot (42 m) high standpipe to hold water. In addition to being used for firefighting, the pressure in the pipe could be regulated to control water surges in the area. Together with the adjacent Chicago Avenue