Cooper,
This is actually a very good question.
Buildings 1 and 2 might make sense in the scenerio I presented (Northwoods Documents) but...
Why building number 7?
Answer: Insurance Settlement
Larry Silverstein heads the consortium that signed a rental contract for the WTC towers and WTC Building 7 with the Harbor Authorities of New York and New Jersey just seven weeks before the 9-11 attacks.
An icon for financial power, built in the early 1970s at a cost of $750 million as part of a massive urban renewal project spearheaded by America's Rockefeller family, the landmark towers anchored a seven-building complex spread over about 12 city blocks.
Silverstein Properties agreed to lease the towers and surrounding Port Authority properties for $3.2 billion over 99 years, with $616 million paid up front. (This $3.2 billion was, according to the actuaries, present discounted market value.)
Silverstein took out insurance cover of $3.6 billion on the WTC properties just 6 weeks before 9-11, then sought to recoup $7.2 billion from insurers on the grounds that the two hijacked airliners that struck the 110-story twin towers Sept. 11 were separate 'occurrences' for insurance purposes, entitling him to collect twice on the $3.6 billion of policies. In September 2003 the U.S. Court of Appeals turned down Silverstein's efforts to double his insurance recovery for the WTC loss. However, His investment in these three buildings seven weeks prior to 9-11 still proved to be very lucrative.
http://www.washingtonpost.com/wp-dyn...-2004Dec6.html