Alot of those square miles have forty or seventy or ninety stories sitting on them too. It adds up.
Empire State Building: 104 floors
Chrysler Building: 77 Floors
Trump Tower: 72 Floors
Citicorp Tower: 59 Floors
MetLife Building: 59 Floors
Conde Nast Tower: 48 Floors
I was suprised to learn this. I find it interesting that (because they are on islands) NYC and Hong Kong are about the only cities on the planet that can actually justify skyscrapers, and both are falling way behind in representation.