United Nations

Peek into the hallowed headquarters of the UN on an hourlong guided tour (prebooking required; check in at the visitors office at 801 First Ave). It's gratifying to see the very meeting halls so often captured in news photos, and to glimpse the interpreters' booths and other odd corners. The whole place has the mid-century flair you'd expect in a complex designed by Le Corbusier and Oscar Niemeyer. Bonus: an extremely eclectic art collection, donated by member states.