Yes! That's it. I will explain in broader spectrum of why I think explosives were planted inside the buildings before the attacks took place.
Here is why I have a problem with the official explanation of why the buildings collapsed as it is filled with contradiction...('cuse my sloppy english, I'm eating on a break, thinking and explaining all at the same time ha)
FEMA stated that fire weakened the structure in the area of the impact hole therefore the heavy portion of the building above the impact hole gave away and acted as a hammer to push down the floors causing it to pancake on top of one and other. The reason there was visible puff of smoke shooting out of buildings and the pulverizition of concrete was because air was pulled in and shot back out as it was collapsing (snickering).
Ok now let me start from the top. As the top portion of the building gave away, there were far too great volume of dust already spewing forth out of the impact hole of the building. While the top part was falling, it was already breaking into pieces, therefore the weight wasn't heavy enough for the top portion to act as a hammer. Each and every floors were pulverizing into dust and small bits, the only logical explanation for the was because there was a great deal of energtic supersonic waves in which high explosives have the ability to produce. The reason you see puff of smokes ejecting at accelerating speed, the reason there were witnesses who heard something that was going "pop pop pop", was because they were most likely explosive charges, which has the ability to reach the temperature as high as 5000 degree F, exploding, breaking the central steel core into pieces to "weaken the steel columns structure of the building". The buildings came down in a free fall manner in only 10-13 seconds, with every 10 floors falling every second. If the pancaking of the floors was true, then each floor that pancaked on the top of the floor below would've slowed down during the process of the collapsing. After the complete collapse, the billowing of the dust was too great and moving at high speed, covering most part of manhattan. The explanation of this has to be because of the high percentage of the concrete, abestos, office supplies, etc, etc in the building were transformed into nothing but dust. The north tower collapsed for the same reason as I explained above. The twoers were built to withstand high winds, earthquakes because it was "ridiculously over engineered."