May be this is mentioned in the video above.............
The Twin Towers had asbestos coated steel structure built in the 70's...........therefore the City of New York had condemed the two towers as a health hazard.................
so the owners sold the towers to a new person......Mr Goldstein who promptly bought insurance for $20 Billion dollars on the towers coverage included act of war or terrorist attack................
The cost to a private company to clean up the asbestos was prohibitively high......
so was it a coincidence that both towers collapsed so soon after the planes struck....
a few days before 9/11 towers were closed to public for safety inspection..........
some think it was during that shut down; explosive devices were installed ...........
Make your own conclusions who did what after that............time will tell.....maybe?