Now lets assume it was aliens!
Now it was wizards!
But what if it was Jesus Christ who did 911?

That was a fun game, but I think you lose.

Is in School for engineering

The buildings of the world trade center were steel structures. Unlike other skyscrapers that use concrete and steel, steel buildings are known for collapsing by fires. The north tower and south tower as well as World Trade Seven collapsed due to extreme heat as well as structural damage to the internal supports resulting in the way they fell. The south tower fell faster due to where the impact of the plane took place. The entire weight of the building was supported on the shell of the building. It couldn't hold it and it collapsed. The North Tower was hit further up and center, evening the weight distribution between the remaining supports. However the damaged part of the building acted like a furnace, super heating the metal to the point of failure causing its collapse. World Trade Seven suffered an unknown amount of damage due to the North and South Tower's collapse. This added to the fires resulted in the eternal supports failing resulting in its fall. if you were to pay attention to the windows near the top you would see light shining though. That is the roof falling though the steel shell of the building. With nothing holding it together the rest of the steel superstructure collapsed