Why is Manhattan skyline missing tall buildings in the middle?

Looking from either east or west one sees that there are a lot of skyscrapers in Lower Manhattan, south of Canal St., and then there are not many at all until you get to the upper 30s going up to Central Park. My question is: Why did the development of skyscrapers in Manhattan occur primarily in two... show more Looking from either east or west one sees that there are a lot of skyscrapers in Lower Manhattan, south of Canal St., and then there are not many at all until you get to the upper 30s going up to Central Park. My question is: Why did the development of skyscrapers in Manhattan occur primarily in two concentrations, evidently ignoring the 50 blocks of Manhattan Island between them?

http://en.wikipedia.org/wiki/File:NYC_Pa...
1 answer 1