Impulse dynamics and catastrophic rupture are key pieces to the question at hand. The high strain rates and shear impulse seen in the floors not damaged by the fire (diesel generators on lower floors) when the damaged floors buckled and gave way. Here is video that shows some key aspects on the integrity of WTC7 and why it fell. https://www.youtube.com/watch?v=tbPpK-oWdYc

@DarkMath I really believe that the attention on WTC 7 is a distraction from the advanced cryptographic communications these terrorists were using that enabled them to deploy this horrible attack.

Here are some details worth your time.

A wired http://archive.wired.com/politics/law/news/2001/02/41658?currentPage=all

Bin Laden: Steganography Master?

by Declan McCullagh 2:00 a.m. Feb. 7, 2001 PST

http://www.freerepublic.com/focus/news/690489/posts

https://www.giac.org/paper/gsec/1943/steganography-evil-hear-evil-speak-evil/103398

Steganography- See No Evil, Hear No Evil, Speak No Evil. Chris Farrow GSEC Practical v1.3 May 13th, 2002

Abstract

With the world focused on terrorism propagated by poor security and businesses suffering from huge economic losses due to computer crime, information security has become a top focus of IT departments. Corporations have begun to heavily implement strategies to secure their workplaces and the information associated with their business. Security tradeshows have sprung up around the globe and organizations are spending significant portions of their budget on training and outsourcing. Yet, despite this revival in information security there are still entire fields of security that remain virtually unknown. Of these, steganography provides not only an exemplary tool for protection of intellectual property and a medium of private communication but also a serious risk to the security of an organization. Amazingly, a simple search of online stores for steganography books and courses finds this subject to be almost unheard of. Further research for steganographic focused vendors shows there is a serious lack of strategy and defensive solutions for the corporate world. This paper is intended to explore the legitimate and malicious uses of steganography and the lack of defensive strategies to counter steganographic techniques. To adequately understand the subject material, the paper provides background information on the history of steganography, an overview of different types of steganography and popular steganographic tools.

https://www.giac.org/paper/gsec/3494/steganography-age-terrorism/102620

Steganography: A New Age of Terrorism

“Steganography is the art and science of communicating in a way which hides the existence of the communication’ (Johnson). According to nameless “U.S. officials and experts” and “U.S. and foreign officials,” terrorist groups are “hiding maps and photographs of terrorist targets and posting instructions for terrorist activities on sports chat rooms, pornographic bulletin boards and other Web sites” (Schneier). Three years ago, FBI Director Louis Freeh tried to convince government authorities that terrorists were using encryption and steganography to support their organizations. Freeh urged legislators to enact stricter Internet usage laws, emphasizing that ignoring the issue would not only cause harm to the United States, but that it would make the fight against terrorism extremely difficult (McCullagh). Today, terrorist organizations such as Hamas, Hezbollah, al Qaeda, and others, are employing advanced steganography techniques to pass sensitive communications across the Internet, undetected. In the wake of several highly coordinated and deadly terrorist attacks, the United States government, and indeed, the world, is hastening to discover viable methods for the detection and prevention of this electronic subterfuge, in the hope that denying criminal networks (the use of the Internet as a communications medium) will render them incapable of mounting another attack that could cost more lives.