It's a really big chore to write all about it.
First thing I'm going to point out is how popular mechanics is relying on the National Institute of Standards and Technology ( NIST = Government ) And the Federal Emergency Management Agency ( FEMA = Government ). Most anything that strives to debunk 911 is a product of the establishment. Some agree with government's supposed findings others don't.
The article is geared toward discrediting conspiracy theory. They don't include images, while images of each scene are at our fingertips.
It's important to note that experts around the world are in disagreement with the NIST report on how WTC 7 fell down. Aside from it being impossible for a building to collapse due to fires alone, it's never happened in history. If it were that easy to bring down a building, it would be cheaper and easier to simply set them ablaze.
Some examples of steel frame structures that burned bigger and longer than WTC 7.
What happens is concrete and brick will strip away, if the debris were removed, we see the steel frame standing. Compare these images with the WTC7 footage and use your own discretion.
It's common sense for us to know, if we set fire to a model of a building make of sticks, it wouldn't just collapse all at once. It's the same thing for large steel buildings. Even in the cases where the steel is warped, the building would gradually begin to sag, and due to "the structural integrity of steel" it would topple over if the temperatures began to reach melting points. In the case of WTC7 the building wasn't totally engulfed in flames, though the other side was heavily fractured from the steel that was catapulted from the twin towers. As a matter of fact the steel from the others, the twin towers, was reported to have been flung as far as 600 feet.
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The media airs remembrance two planes striking the twin towers and the victims, despite 4 planes crashing that day.
Flight 93. A Boeing 757 allegedly disintegrated in a field in Shanksville Pennsylvania. The original report suggested that the plane was so disintegrated they couldn't find any piece larger than a telephone book. Aside from the first 3 steel frame buildings to fall from a fire in all of history, Flight 93 would also be the easiest air bus crash to clean up.
No plane was found, and this footage will never be revisited on 911.
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Flight 77. The one that allegedly struck the Pentagon
There are 2 known surveillance videos that captured anything pertaining to this. Despite claims of conspiracy, the FBI released footage of the explosion, and edited out some frames, so only the explosion is visible. The 2nd footage was ceased from a hotel, after a very recent lawsuit the video was released and off in the distance we see an explosion, but nothing before that. Bad angle anyway.
I'm feeling a bit lazy at the moment to post an image of the aftermath seen at the pentagon on 911. Google it.
To point out, the Planes that struck the twin towers had no problem cutting through steel and going right into the building. The hole on the Pentagon however, wasn't anything like the 38 meter wingspan of a Boeing.
Again, Popular Mechanics is sub servant to NIST.