This story originally appeared in the Spring 2014 issue of Preservation magazine.

How do you preserve a place that’s already gone? That was the question Poughkeepsie, N.Y.–based nonprofit Scenic Hudson asked Mathews Nielsen Landscape Architects in 2006, when it tasked them with restoring and reinterpreting a historic site along the Hudson River. The result: a bucolic yet educational outdoor museum.

The West Point Foundry in Cold Spring, N.Y., opened in 1818. It was a pioneer of vertical integration, in which every aspect of manufacturing—from extracting raw ore to selling arms—occurred on the same site. The foundry supplied objects such as Parrott rifles during the Civil War and pipes for New York City’s water system.

By the time Scenic Hudson acquired the foundry’s 87 acres in 1996, the National Register-listed site was in effect a woodsy junkyard. Just one 19th-century brick office building remained intact. “While most of the foundry buildings have disappeared, so much remained below ground that could be researched and interpreted,” says Rita Shaheen, director of parks for Scenic Hudson.

“We set out to understand where all the building complexes were and their function,” says Kim Mathews of Mathews Nielsen. Scholars from Michigan Technological University’s Industrial Archaeology program spent six years unearthing some 145,000 foundry-related artifacts and tracing the footprints of its 15 or so buildings.

Working with New York’s State Historic Preservation Office, Scenic Hudson, Mathews Nielsen, and Li/Saltzman Architects developed a $3.6 million public access and interpretation plan to stabilize many of the site’s ruins and guide visitors around them. Since 2014, they have stabilized the masonry walls of the pattern shop, machine shop, and casting shop, and restored part of the exterior of the brick office building. Fifteen markers, mounted on poles, tell the foundry’s story. Each one corresponds with an audiovisual tour that connects to visitors’ mobile phones and tracks their position using GPS.

Interpretive elements recall the past without re-creating it. A stainless steel sculpture evokes the 36-foot-diameter water wheel that once stood on the site. Another sculpture of a gun platform stands on the marsh’s edge, where Abraham Lincoln watched the testing of Parrott rifles over the Hudson. “We didn’t want it to be a theme park,” says Mathews. “We still wanted it to be a walk in the woods.”

To minimize the impact on the land, the trail follows the original rail route, which brought finished goods to the river for shipping. Local artisans crafted benches from sustainable black locust wood grown in the region.

One addition raised eyebrows of preservationists and townsfolk alike, despite its environmental benefits. The most difficult item to get approved was not on the grounds but in the parking lot. “We added a composting toilet,” says Mathews.