I visited New York in September for a series of meetings with OpenPlans about organizing a Transportation Camp in Washington DC during the Transportation Research Board Annual Meeting in January 2012.
While there I was able to visit the High Line, an old aerial railway line that ran along the west side of Manhattan. The rail line has been converted to a walkway and is probably one of the most successful urban design projects from the last decade.
If you go to New York be sure to take a walk on the High Line. All my NY High Line photos on Flickr.