The artificial hills on this artificial chunk of island are genuinely amazing. Spanning only 10 acres, the expertly engineered outdoor space makes for a remarkable day trip. Roam Discovery Hill, a 40-foot-tall mound with trees and shrubs, and art installations like Tree Chuangs; climb Outlook Hill, a 70-foot-tall lookout spot with unbridled views of Lower Manhattan, the Statue of Liberty, and the Verrazzano Bridge; and ride NYC's longest slide (57 feet long and three stories high!) on Slide Hill. When you're ready to get off your feet, lie out on Grassy Hill, a slightly smaller hump with an equally breathtaking vantage point.