There seemed to be a few questions concerning the 911 commission report. Evidence pointing toward the twin towers and wtc 7 being a controlled demolition:
The time it took for the buildings to collapse. The time was near free fall speed, which means there was little to no resistance in the building. The theory in the 911 commission report said that the pancake effect caused each floor to collapse on the next floors, which created a domino effect. However i find this very hard to believe since the buildings did collapse at near free fall speed.
The large dust clouds of concrete. It does not seem like the concrete can be pulverized to dust just from collapsing.
Chemical evidence showed that thermite was used.
The design of the building showed many steel columns that somehow just got destroyed.
Discuss.
If you want to watch a video, here is one that focuses mainly on the science of it.
September 11th Revisited: Were explosives used?