Grand Theft Country Home

In the film World Trade Center: Anatomy of the Collapse, we see Professor Abolhassan Astaneh-Asl from the University of California at Berkeley who is interviewed and shown investigating the collapse in the New Jersey 'scrapyard' where roughly 20% of the steel wreckage from the WTC was brought. [The other 80% was immediately sold to countries like China, Malaysia, South Korea & India.] He first states: "I couldn't believe it. I couldn't believe that it actually collapsed the way it did. Like everyone else, it was totally out of your human capacity to digest it and absorb it."
He then leads us to one of the exterior column assemblies and proceeds to explain:
"What you see here is actually very critical - very, very important. Perhaps, this is the most important piece I have found so far. ...This is the inside face of [the] back columns. ...What you see here is, first of all, it bent. That was due to [an] explosion - but more importantly - this has a signature of [an] explosion. This has happened due to explosive material hitting this column and making that bulge. So this is [the] floor where [an] explosion happened, and the windows are blown away. Everything is burned. Even [the] fire-proofing on this floor is burned and glazed to the steel."
Although the Professor relates the signatures to blasts from the planes, it is not certain what floor the piece we see actually came from. The important thing is that there have not been many people at all that have been able to get close to the wreckage -- let alone have a camera recording images of blast damage with an expert saying "explosions did this."
Interestingly, the film then adds that the fire-proofing was blown off, and lets us know that even though every beam had been fireproofed, very little of the coating can be found.