The building is known for one colossal engineering mistake.  It was originally clad is Carrara marble, but one piece fell off the building and an inspection found cracks in other pieces covering the building.  In 1985, the owners tried to alleviate the problem by stainless steel straps to hold the marble in place.  That apparently proved to be an unsatisfactory solution.  Beginning in 1990, the Carrara marble was replaced with Mount Airy granite at an estimated cost of somewhere around $80 million.