No matter how much the truther's architects/engineers yammer about controlled demolition and how the towers collapsed, they're wrong.
They didn't collapse they dustified as Dr. Judy Wood investigation testifies.
9 seconds into this video you can see the steel 'spire' literally dustify.
Concrete slabs and steel peeled and dustified while the towers were coming down. Bldg 7 dustified from the inside and fell as a hollow shell.