UPDATE: I did some googling and found that the actual history was a little different than I remembered. I am letting the rest of this post stand, but see essays like [link|http://globalresearch.ca/articles/NOR309A.html|http://globalresearc...cles/NOR309A.html] for what I believe to be a more accurate history.
The main reason that the Twin Towers actually got built was as a tribute to man's ego. Or rather a man's ego. The man in question being Robert Moses.
Whatever else they came to symbolize to the world, they were built as a monument to a monumental ego. They were to be the single most visible symbol of how he reshaped New York City.
Regards,
Ben
PS Trivia of the day. The reason why Central Park has such low bridges was because Moses didn't want "his park" enjoyed by blacks. Blacks tend to go places in busses, and the bridges are too low to accomodate busses.