The North Tower Fire And Collapse
Update: See the update at the bottom.
Is the subject of a coming post, but here's a picture that demonstrates what extraordinary stresses the building was experiencing:
Note the many severed columns along the West (left) face of the building. Note the very evident buckling of the South (right) side of the building.
Update: Mark (Gravy) Roberts checks in to say that he doesn't believe any of the columns on the West face were severed. Looking closely at the photograph it appears that I may have been misled by the darkened color. I can see in the middle that some of the blackened columns do appear to be continuous. There certainly does appear to be some bowing visible in the southmost columns on that face of the buiding. But I cannot be positive that the extent of severed columns is as great as I represented originally in this post.