• Construction start: 1970
• Construction finish: 1972
• Designed by: Edward Durell Stone & Associates and Perkins and Will Corporation
• Cost: $120,000,000.00
• Type: Skyscraper
• Stories: 83
• Maximum Height: 1,136 feet / 346 meters

• Stories above ground: 83
• Stories below ground: 5
• Floor space: 2,500,000

• 1972: Construction is completed.
• 1973: The Sears Tower surpasses this building as the tallest building in Chicago.
• 1974: A slab of marble facade comes off the building and plunges through the roof of the Prudential Center Annex.
• 1989-1992: All 43,000 marble panels comprising the building's facade are replaced with granite from North Carolina. The marble panels were buckling and coming loose because of the harsh Chicago winters. It cost between $60- and $80,000,000.00 to replace all the stone.
• November, 1991: A routine inspection finds that two steel columns in the building's lobby have to be reinforced. The Chicago Tribune reports that although building officials say there is no danger, additional steel plates are welded to the columns in question.
• 1998: The Amoco Building is sold. The exact price is never made public, but estimated to be between $430,000,000.00 and $440,000,000.00.
• January 1, 2001: The building's name is changed to Aon Center.
• May, 2003 : The Aon Center is sold for $465,000,000.00.
• March, 2007: A plan is floated to convert the top 13 stories of this tower to residential apartments or condominiums.

• At the time of its completion, this was the tallest building in Chicago.
• At the time of its completion, this was the fourth-tallest building in the world.
• The building's original marble facade was from Carrara, the same Italian quarry used by Michaelangelo for his masterpiece "David."
• This building is connected to the city's underground pedestrian tunnel system.

• The sculpture made up of hundreds of rods sticking out of the ground is called "Untitled Sounding Sculpture" and was made by Harra Bertoia. The rods are 19 feet tall and make an especially eerie sound when the wind blows through them at night.

• The sunken plaza is a great place to cool off in the Summer when the fountain is on. And if it's off there might be a book fair or some other event happening worth checking out.

• Bunnies. There are a number of rabbits who make their homes in the decorative planters on the Aon Center grounds. They are most visible when they come out at night to eat in peace.

• "...the worst thing that has happened to Chicago's skyline in the last 30 years."

  -Paul Gapp, Chicago Tribune, 1974

There are 10 comments.

  One of the best in Chicago after the Hancock.

Northshore Process Service - Wednesday, September 10th, 2008 @ 4:57pm  

  When this building was redone they trashed the Bertoia fountain. What is left is heartbreaking to one who loved the original.

Roger Marz - Monday, May 26th, 2008 @ 6:34pm  

  i loved this building. the design is simplicity itself. the plain white facade and the lights at night are just beautiful. the location on the skyline is genius. there is no chicago without the Aon center.

Dr. Q - Monday, October 29th, 2007 @ 2:53pm  

  One of the best in the US behind the Hancock. Big Stan really deserves some credit.

William Hopkins - Friday, April 27th, 2007 @ 10:06pm  

  The Aon Center is a building you have to love to hate. its such a cold building, but has a very nice plaza at the base.

kirby cruz - Thursday, December 7th, 2006 @ 8:37pm  

  My feeling for this building has nothing to do with the WTC, it has to do with how the building soars. In my opinion no building in Chicago feels taller when looking at it from the base then this one. With no setbacks or tapers, the entire height of the building is viewable from the great plaza at the base.

Jeff Kemp - Thursday, June 22nd, 2006 @ 6:34am  

  I think some people get caught up with this building's apparent similarity to the WTC. (COMPLETELY different structural system, thank God.) Don't let emotion get in the way of the fact that this building has never found an audience; perhaps because it has no human reference (you just get dwarfed by the building, not invited or embraced.) Functionally, it does everything right; but I don't think anyone will ever love this building, like you do the Marquette or the Field building (now the LaSalle Bank bldg) or the BOT. (And don't get me wrong: I think the UBS and the new Hyatt are both great additions. Old ain't necessarily better.) But the AON Center just BORES me.

Dean Skora - Thursday, April 20th, 2006 @ 2:41pm  

  i think it is a wonderful tower and also the closest thing we can manage to one of the twin towers. This building would be better if it had a twin and it will also honor the twin towers in new york.It gives chicago a much better skyline helping the sears tower and and the Hancock tower.

Mario - Monday, August 29th, 2005 @ 10:26pm  

  I also gave this 70's look 5 stars. the Chicago skyline has changed over the years and this building with the other 2 Sears offsets and Hancock long taper give the Aon a difinate contrast. Good stuff !

william lomasney - Tuesday, April 19th, 2005 @ 9:58pm  

  I really like this building even though I admit it is plain. I like it for its height, facade, and lighting at night. The plainnless is ok because this building helps to create balance in the Chicago skyline. Its location is also perfect relative to the locations of Sears and Hancock. Also worth noting is that this building has the closest resemblence to a WTC tower. I think it would be cool if they put another AON center right next to it to pay tribute to the WTC center. However, I am not sure how NYC would feel about this.

Charlie Shellenberger - Wednesday, March 16th, 2005 @ 9:27am