You've probably heard of it. New York City's newest park received enormous attention for years before it even opened. Boasting a coterie of celebrity backers, the converted elevated rail line became one of the most celebrated and anticipated public projects in recent memory. Now the park, brilliantly designed by James Corner Field Operations, with Diller Scofidio + Renfro, is open, and it is everything that was promised and more. The interaction with the city and the transformation of blighted infrastructure into beautiful park is an impressive accomplishment. So now the gauntlet has been thrown down: What city is going to one-up New York?