Landscape architecture firm Nelson Byrd Woltz, founded more than three decades ago, made its name through ecological restoration in rural areas and has won dozens of international design awards. But it has become known for a project that’s distinctly urban: The firm is designing the landscaping for Hudson Yards, a $25 billion development project on the west side of Manhattan. NBW has engineered a park that will sit on top of a railway center, obscuring the mess of train tracks that connect New York to New Jersey. It’s basically a big green roof, complete with cooling and ventilation systems, rainwater storage, and irrigation—not to mention the 225 trees and 28,000 plants that will grow above the tracks when the park is completed in 2025. The project is indicative of principal Thomas L. Woltz’s belief that urban parks should be designed with both cultural and ecological factors in mind.