The World Trade Center Buildings Are Less Sturdy Than the Empire State Building

The twin towers were hitb bowing seven 60 sevens, which were much larger planes. The world trade center was only 22 % as dense as the empire state building - making it less sturdy to airplane strikes. They had a steel and concrete corps, but they did not have the same kind of supporting columns further out from the core. So the individual floors were supported instead by light weight steel trusses.