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
Vista Tower (Chicago) Vista Tower (Chicago) Construction started in August 2016 with expected completion in 2020. Upon completion, it will become the city's third-tallest building at . Designed by a team led by architect Jeanne Gang, Vista will supplant the nearby Aqua skyscraper (also designed by a team led by Jean Gang) as the tallest structure in the world designed by a woman. This will make Chicago home to the two tallest structures designed by a woman. Vista Tower is a joint project of Magellan Development Group and Wanda Group. The original estimated cost of construction was $900 million. The building will have