The Aon Center, Chicago

The Aon Center, erst the Amoco Building, is that the third tallest building in Chicago. At the time of its original construction, and for a brief time once, it was the largest marble-clad building within the world. it absolutely was conjointly a hazard for folks walking at a lower place it.

The thin slabs of marble, created nearly entirely of the mineral spar, were unable to face up to Chicago’s harsh climate, and that they began to warp and fall off as shortly because the building was completed. during a biennial project ending in 1992, the marble was replaced with granite. The K-feldspar and quartz of the granite ar higher ready to handle the weather, and pedestrians will yet again walk at a lower place the building safely.