After 9/11, I always hoped they would rebuild the WTC bigger and better. So I put what was in my head into a model. Some of this was originally Peter's (credit). This is just the steelwork. I'll be uploading more soon. Anyway, this steel configuration would provide more protection and prevention of a collapse. This is twice the amount of steel that was in the old WTC. The structure of the two buildings is very different, but the exterior columns remain the same to make the building seem identical to the old one. The interior is composed mainly of marble to hide the reinforced concrete. When attacked, the building demonstrates a resistence to the force against it (aka: airplane). When an object impacts the surface of the building, the outer columns (which also give the building its original beauty) slow the object down before it reaches the core, the spine of the building (includes all escape routes, electrical wiring, water pipes, etc.). By the time the object reaches the core, it isn't a major threat. Therefore, the core won't be damaged, providing support and escape. Filters are included within the air ducts to prevent circulation of toxic smoke. Stairwells are pressurized for the same purpose. Fireproofing has been enhanced to remain intact in the event of an explosion (this is what casued the collapse of the oringinal buildings). The idea is to get people out of the building safely and have the building itself remain standing.