Originally Posted by MediaGuy

Well that's the whole point of steel frame building construction - they don't topple, they're made of thicker, stronger constituents at the bottom than at the top, and they're embedded so firmly in the ground that even a great earthquake only makes them oscillate.

If a scenario were so cataclysmic as to induce two of the most structurally sound buildings in the world to start collapsing, I don't think the rest of Manhattan would have much of a chance anyway.

Are you saying they had built-in weakness points that would cause them to fall in on themselves in case of a major fire?

Do you mean the "weakness" points were provoked, that the stronger, sounder section below the crash points were removed by means that your statement there would appear to be implying a system was in place that would cut through steel, steel joints and support beams rapidly in order to allow a vertical descent that would prevent worse damage?

:D