United Nations Headquarters, Turtle Bay

The 18-acre United Nations site on the east side of Midtown Manhattan is officially international territory. The 39-storey Secretariat was the first high-rise building in New York to use the curtain wall, albeit on its east and west elevations. It was designed by an international team that included Le Corbusier, Oscar Niemeyer and Wallace Harrison, and is the centrepiece of the complex which includes an assembly building and library.