The Aon Center designed by architect Edward Durell Stone and completed in 1972 - second tallest building in Chicago. Originally built, it was the world's tallest marble-clad building, but when the marble sheating started to come off, it all had to be refaced with granite

The Aon Center designed by architect Edward Durell Stone and completed in 1972 - second tallest building in Chicago. Originally built, it was the world's tallest marble-clad building, but when the marble sheating started to come off, it all had to be refaced with granite