I don't know if many of you have noticed, but when the tipping tower (Iget north and south confused) Begins to tip, if you look about halfway up the upper section, you'll see the corner appears to blow out for no real reason and there is a bright flash just to the right of the corner blowing out. It can be seen in the I think "total dimemberment" part of twin tower section of A&E for 9-11 truth's dvd. There are more flashes as the top part descends into the dust cloud, and even many small flashes below the colllapse zone although non-conclusive. Comparing to the rest of the picture there are no what could be photgraphic glithes in the other tower's smoke, fire etc.
Some think the flashes are too short in duration to be explosions, but they are there. And flashes on bridge demolitions are very short in duration. I think its the bismark south dakota memorial bridge that shows what is described as military incendiaries by some news accounts and the u-tubes of phase one and two show what seems like thermate charges cutting the girders while high explosives fracture the concrete supports. The thermate sounds like loud firecarckers compared to the booms of the charges taking out the concrete. I think its a good example for those wanting to see such demolition without any building materials in the way. Its just the steel beams of the bridge sections. I'll try to get back with a link.