New York Harbor, where the mighty Hudson River empties into the Atlantic, is one of the largest natural harbors in the world. It is at the same time a highly engineered environment.

Drawing on both these facets—the natural and the man-made—is Little Island, which is transforming a former industrial jetty into idyllic public parkland, at a cost of $250 million.Situated within Hudson River Park, Little Island rests aloft the remains of Pier 55 on Manhattan’s West Side on hundreds of stepped bulbous concrete piles.

When it opens next spring, the hilly landscaped refuge will offer visitors walking trails, a public plaza, and a pair of performance stages, among other recreational spaces. Delineating these uses will be a smorgasbord of native flora, ranging from dozens of tree and shrub species to hundreds of types of grasses and perennials, all nestled atop the giant concrete “tulip pots.”

The London-based design firm Heatherwick Studio was awarded the project in 2013 following a design competition chaired by Barry Diller and Diane von Furstenberg. While the idea of a levitating park was plenty whimsical, the architects showed real concern about disturbing marine life habitats, for which Pier 55 functioned as scaffolding.