The pandemic changed the types of projects that lead a city’s tourism brochure: Starchitect-designed museums are out and dynamic green spaces are in. “Access to fresh air, open sky and nature is now our priority,” says Richard Kennedy, senior principal of James Corner Field Operations, “as is providing equal opportunity to experience something, so you’re not privileging one audience. Parks are the democratic spaces of a city.”

Granted, the new six-hectare landscape that Kennedy’s team recently completed on San Francisco’s north side long predates the shift to outdoor gathering: Presidio Tunnel Tops is the culmination of a decades-long infrastructure plan to bury a key urban roadway. The finished project carves walking trails and drought-tolerant gardens into bluffs that sit directly atop seven lanes of the 101 highway. It also reconnects two important U.S. National Parks — the windswept waterfront of Crissy Field and the parade lawn of the Presidio, a former military base — that had been split up by the highway since 1936.

Just as the firm’s High Line project reframed views of Manhattan’s West Side by lifting pedestrians 10 metres above the sidewalk, so does Presidio Tunnel Tops’ mix of spaces — which include cliff walks, a campfire circle, picnic grounds and a bridge-facing amphitheatre — offer a unique 360-degree perspective that was inaccessible for 86 years.

“With just that [12 metres] of elevation above the beach, you see the Golden Gate Bridge, Marin Headlands, Mount Tam and Alcatraz,” says Kennedy. “Then you turn around and see the city and the Presidio’s red brick barracks. It’s everything I like about the bay: nature, this unique collection of history and creative industry, and the mixing of people in public spaces.”

Originally projected to welcome half a million people in its first year, Presidio Tunnel Tops saw 600,000 visitors in its opening two months. And repeat visitors can follow along as the gardens transform: More than half of the park’s 200,000 plantings were grown in the Presidio’s own nursery from seeds harvested within the park. “The younger you plant material on a windy site, the more resilient it becomes to the wind,” Kennedy says, referencing the Golden Gate’s notorious gusts. “Our client here has the long view: They’re building this project to serve for the next five to 10 generations. They have all the patience in the world to let this garden become itself over time.”