A steel-framed building is not likely to fall even enveloped in flame. When the Mandarin Oriental burned in February of 2009, Comparisons with World Trade Center fires were inevitable.
On September 11, 2001, World Trade Center 7 collapsed into its footprint.
Two airliners had crashed into the twin towers, buildings 1 and 2, at 8:46 and 9:03 A.M., respectively. They had fallen soon afterward.
On the far side of the 8-story building 6, and across Vesey Street, about a hundred meters away from the towers, the 47-story Salomon Brothers building (World Trade Center 7) started burning in at least one small area. At 5:21 P.M., it fell straight down.
There are occasions when steel buildings fall straight downward. The sequence of events requires the loss of support along horizontal planes. So it appears that World Trade Center 7 was destroyed by controlled demolition.
It would likely take longer than a day for any demolition crew to prepare the orderly destruction of a large steel frame.
This was the most-complicated day in the history of New York City.
There were sporadic flames. The possibility that workers installed explosives within a few hours and that they did so with any precision in a structure that was burning and on that day is a bit of a stretch.
Not impossible but extraordinarily difficult. It's näive and childishly credulous to accept any simple explanation uncritically.
And so, the question remains....
What happened at World Trade Center 7 on September 11, 2001?