Most wind turbines are located in remote areas as isolated towers or farms of towers each having a single turbine. New designs discussed by Knight (2004) would bring multiple turbine to the tops of buildings in major cities. A possible design choice for the replacement to New York City's World Trade Center is building with multiple turbines on top. It would have height of 1,776 ft.
Reference
Knight, J., 2004: Breezing into town. Nature, 430, 12-13.