Initial, secondary. How come nothing of the towers remained? Those pristine lower floors the survivors evacuated before reporting the sound of explosives when there was NO FIRE in the lower floors? And what part of straight down don't you understand when there was commercial airline sized DIRECTIONAL IMPACT THAT DIDN'T PENETRATE THROUGH THE INNER SUPPORT OF THE BUILDINGS? How come it didn't fragment out in the direction the 'exoskeleton' was weakened and where the most additional weight came to rest in and around it plus the burning jet fuel? Your other view clearly shows the thick black jet fueled fire smoke considerably higher than the point of collapse which is the lower grayish mushroom below. Maybe you haven't witnessed the purposeful decimation of a structure with explosives before. I have. Maybe you've never witnessed a fueled vehicle explode and burn out. I have. Maybe you have never seen an oil field burn, I have. In the oil fields of the east they burn the impurities instead of reusing or refining another fuel or oil. That smoke is black. It stands to reason that the hhottest point of the fire caused by the impact of the planes would be the floors where it hit and those directly above. Why then would the building shown in the photo you provided have a second, cold mushroom of pure concrete dust well below the point of impact?
You have no proof whatsoever to claim there was no damage to the interior columns. NONE.
I don't care what you say you witnessed because you have no proof of that either.
You claimed that the collapse started in the bottom of the towers 'cause that is the way pros do it'..
I show you indisputable photographic evidence that you are wrong.. And you come back with 'directional impact that didn't penetrate through the inner support'..
LMAO