I would venture to guess that even with a well engineered building, time will through in some chaotic aspects that were not allowed and result in failure, war comes to mind.
Mother Nature really has nothing better to do. Gravity always pulls things down, wind likes to knock things over, and water tends to get everywhere we try to keep it out of...
Some interesting reading I just picked up:
The World Without Us And a cute little video based on the book:
YouTube Video Link 
