There are instances when an engineering error is actually a good thing. While the Leaning Tower of Pisa (Italy) might appear as if it is about to topple over, it is much more stable than you might realise. As per Camilo Nuti's explanations, due to the soft underlying soil, the same soft one which caused the tower to lean, the ground is actually able to absorb earthquake vibrations that might otherwise prove devastating. So, a bit of rumbling will be taken in stride.