Central Park is a massive park. Pick a New York based TV show and they will show an aerial shot for sure and undoubtedly any trip to NYC should include a visit whether it is for a picnic, playing ball, the adjacent Guggenheim (WHS!), jogging in the morning, playgrounds, cycling, the "castles", overpriced corn dogs, take a carriage ride, see mounted police, and according to Law & Order you can find bodies in the bushes *chung-chung*

In short, Central Park is an icon that defines Manhattan as much the Statue of Liberty, the skyscrapers and bridges.

Compared to the few other parks in the world that are considered world heritage, Kew Gardens and the Singapore Botanical Gardens come to mind, I would always prefer Central Park. Whether it is more "unique" it is hard to say. Surely I would agree it is special and nothing is similar enough, but I can't judge it from an objective view *chung-chung*