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
Joshua Sears Building supply store occupied one of the smaller storefronts for over twenty years. At one point the building's upper floors, originally intended for office space, were divided into seven apartments. On August 3, 1982, it was added the National Register of Historic Places. As of 2005 the building housed a religious bookstore and a real estate office. In 2015 the building was purchased by Local attorney Sim Osborn and his wife Monica Hart, the couple bought the building with plans to preserve its historic features and aesthetics for future generations. History Joshua Sears Building The Joshua Sears Building is a historic