The $200 Million Mistake Hiding in Chicago’s Skyline

I need to remember to take my umbrella the next time I got to Chicago in case a 350-pound Carrara marble slab comes tumbling down from a building.

The building in question - now known as the Aon Center - was originally clad in the aforementioned Carrara marble, using panels that were 1.25 inches thick.

Apparently marble isn't terribly durable when going through extreme freeze-thaw-hot-summer cycles with each temperature shift leading to tiny cracks developing which allowed water to get into the cracks and freeze - like pot holes forming on the side of the (initially) world's 4th tallest building. 

Eventually, all the marble panels were replaced with granite which seems to weather the Chicago winters far better and is less prone to hurling itself off the building's facade and onto the tourists looking up with their mouths agape.