Extending from 42nd to 48th Streets and from 1st Avenue to FDR Drive is the windswept United Nations Plaza, where the flags of the nearly 200 member nations flap noisily in the breeze. Legally, the United Nations isn’t part of New York City at all but is international territory. The U.N. has its own post office, postage stamps, and uniformed security force.

Built in 1948, on 18 acres bought and donated by J. D. Rockefeller, Jr., the United Nations complex is made up of three buildings. The vertical greenish glass slab is the Secretariat Building, housing many offices. The low-slung horizontal edifice is the Conference Building, and the dramatic white building with concave sides is the General Assembly.

Only the General Assembly Building is open to the public; to see it, you must join one of the scheduled 45-minute tours, which leave from the visitor entrance at 46th Street and 1st Avenue (212/963-8687, www.un.org, 9:30 a.m.–4:45 p.m. Mon.–Fri., adults $16.00, seniors $11.00, high school and college students $11.00, children 6–14 $9.50, children under 6 not permitted).