New York City,Battery Park Project Piet Oudolf. Photo all rights reserved Piet Oudolf.

Office and residential buildings stand in the financial district of Manhattan in this aerial photograph taken over New York, U.S., on Wednesday, July 7, 2010. Manhattan’s office vacancy rate dropped for the first time in three years in the second quarter as almost 7 million square feet of leases were signed, brokerage Cushman & Wakefield Inc. said. The falling vacancy in New York, the country’s biggest and costliest office market, contrasted with the national vacancy rate of 17.4 percent, the highest level in 17 years. Photographer: Daniel Acker/Bloomberg via Getty Images