I am an structural engineer. Whoever wrote that other article is ignorant of steel buildings. There has never been a steel building destroyed by fire, including ones where explosions occured. As that other reviewer said, there is no way that the impacts on the top floors was large enough to pulverize the concrete. Look at pictures of other buildiong collapses and you will see they look nothing like what happend at WTC. Moreover, building 7 was built entirely differently from the twin towers, yet it collapsed exactly the same way?Wake up and smell the coffee. Sounds like that other "engineer" is CIA or Mosad plant.