There are still many, many questions surrounding 9/11; and one by one, they're being answered. Those who raised eyebrows at what engineers designated as a classic controlled demolition were dubbed "Truthers" and came under attack from Media and "unofficial" officials.
In the meantime, we mourn the 3,000 dead, and in particular, the firemen who sacrificed their lives in their attempt to rescue those trapped in the buildings.
There are those who wish to examine Larry Silverstein, who turned a tidy profit from this tragedy.
His other investors were Lloyd Goldman and Joseph Cayre.
According to the New York Times, he collected $4.5 Billion on an insurance policy with Swiss Re, which, oddly enough, included coverage for "terrorist attacks".
Reportedly, the NY Port Authority had been trying unsuccessfully for several years to get permission to demolish the buildings due to the known asbestos problem.
According to the Arctic Beacon,
"... the only reason the [Twin Towers] building(s) were still standing until 9/11 was because it was too costly to disassemble them floor by floor since the Port Authority was prohibited legally from demolishing the buildings."
Silverstein became the subject of inquiry due to his recorded order to the Fire Department commander to "Pull It" -- an order to demolish Building 7, which had suffered no visible damage from the fires of the WTC, but which was demolished in what was clearly a controlled demolition -- matching the collapse of the Twin Towers. The "Truthers" who claim the validity of this charge consist of engineers and architects, worldwide.
As a footnote, in August 2001, we were advised that the subterranean infrastructure in the Financial District was completely degraded, and that Wall Street firms were creating redundant IT sites in New Jersey in the event there was a physical collapse of the Financial District.
The destruction of the WTC facilitated the renovation of the Financial District infrastructure, and Wall Street and the Port Authority were happy; and the cost was only 3,000 lives.
[Excellent foresight on their part!]