If you don't mind, I'd like to reminisce a bit about what the area was like before the WTC was built, and how WTC came into being:
The part of lower Manhattan later occupied by the WTC was one of the oldest, and most run-down, neighborhoods in the city. The streets that were there--Albany, Greenwich, Cortlandt, Liberty, etc.--had a motley collection of early 19th century (and some 18th century) buildings, which housed stores, offices and some light manufacturing. There were even a few residences. Unlike today's chi-chi NYC real estate, these were tenements whose residents traced their ancestry back to the "potato famine" Irish of the 1848-52 migration. I used to see them playing stickball in Greenwich Street or Trinity Place on Saturdays.
The area had sensational cut-rate shopping. Cortlandt Street was known as "Radio Row" (Arrow Electronics, Heinz and Bolet, etc.)--absolutely the place in the city to buy hi-fi and radio equipment at a time when it was very expensive, and you had to know what you were doing. The original Syms clothing store (men's clothes exclusively at that time) was on Greenwich Street. Kaufman's Army/Navy had all sorts of weird (and highly appealing to a teenager) stuff, like .50 cal. ammunition with the powder removed, dummy artillery shells, knives, pup tents--you name it. Volk's Restaurant, an authentic German place, served sensational fare; the bartenders sold me real Lowenbrau and Berliner Weisse when I was 15 and working for the New York Post (on West Street) as a messenger at night, after school hours. I felt like a real "adult" :p The area under the West Side Highway held junkyards and auto repair places. It was a grungy, raffish, but oddly appealing neighborhood.
The WTC was the brainchild of David Rockefeller. His Chase Manhattan Bank had its headquarters downtown. He was concerned that the deterioration of the area would be bad for his and others' investments. The Rockefellers always had a strong interest in global trade, and Chase was one of the leaders in international lending. He envisioned that lower Manhattan could become an international commerce center. Starting in 1958, he got the almighty Port of New York Authority on his side. The Port Authority had quasi-public powers (including eminent domain) and many exemptions from taxes and construction standards, and could issue bonds on "full faith and credit" of the public. The local business people organized a big effort to stop the WTC. But, before the civil rights and Vietnam eras, such protests came to naught--the Port Authority just swept them away.
I was still working in that area when the WTC was being built. Two things (other than the truly gargantuan size of the excavation) fascinated me most. One was the relatively small, self-jacking cranes that were developed for the project. They attached to the steel framing of the buildings and, as the floors rose, the cranes jacked themselves up the sides of the buildings to continue to haul up materials.
The other was the tubes for the PATH, a commuter subway that runs under the Hudson from Jersey City to lower Manhattan, as well as to midtown. PATH (then called the Hudson Tubes) had its lower Manhattan terminal in the area being excavated for the WTC. In a clever bit of engineering, they excavated around the huge concrete PATH tubes that had been buried deep underground and were now exposed, and propped the tubes up with railroad ties and other timbers. Periodically PATH trains would come rumbling through the exposed tube, shaking them scarily and making the timbers groan, but not cracking the tubes. When the buildings were completed, the PATH station that formerly was a stand-alone on Cortlandt Street was relocated in the lowest level of the WTC. Of course, service to lower Manhattan was suspended after the 9/11 tragedy as part of the PATH station (and some subway stations) were damaged. The PATH tubes, being at the lowest level, filled with water. Within days of the attack, engineers paddled small boats down the tubes to NJ to assess the level of water and the work to be done. Must have been an eerie sight.
Thanks for listening.