Where is the missing 1200 feet of heavy building materials? It was vaporized according to the engineering firm that built the buildings (and helped engineer the demolition of them). Controlled demolition turns buildings into dust at near freefall speed, not 'collapses'. Steel dust? That requires far more energy than a collapse event could produce and still have near full gravitational acceleration (violates conservation of momentum/energy). The buildings were demolished with well placed explosives ..... without a shadow of a doubt, as clear as it can get.