Comment: Or...

(See in situ)

In reply to comment: Or ... (see in situ)

Or...

The towers were designed to withstand plane impacts - the only argument for structural failure is specifically to fire safety and its inability to maintain integrity - which evidently resulted in fires burning at impossible temperatures to be the first ever cause of a steel buildings collapse.

Toppling is the most likely scenario of specific members failing, a free fall collapse is most likely a scenario of most members failing. That should explain everything.

They that give up liberty for security deserve neither.