Drivers passing through Flanders on Route 24 tend to notice it before they can explain it: a 20-foot-tall, 30-foot-long white duck, sitting beside the road, doing nothing in particular except being exactly what it looks like. The Big Duck has been a fixture of eastern Long Island for nearly a century, and its origin story is stranger, and more local, than its roadside-oddity reputation suggests.

Long Island duck farmer Martin Maurer built the structure in 1931 to sell ducks and duck eggs, at a time when duck farming was one of the region's defining industries. The idea came from a trip to California, where Maurer stopped at a coffee shop built in the shape of a giant coffee pot and decided his own farm stand deserved the same kind of architectural stunt. He hired Broadway set designers and local artisans to build it, constructing a duck-shaped shop out of ferrocement over a wooden frame, tall enough to walk into and shaped precisely enough that no one driving by would ever mistake it for anything else. The eyes are a particularly practical touch: two taillights pulled from a Ford Model T.

The Big Duck has spent much of its life on the move. Built originally in Riverhead, it relocated to a spot near Route 24 in Flanders in 1937, when Maurer shifted his farm and shop there. In January 1988, it moved again, this time to Hampton Bays. By 2007, with development plans for that land stalled, the duck made its fourth trip, traveling four miles back to Flanders, where it has remained ever since, closing the loop on nearly seven decades of relocations.

Along the way, the Big Duck picked up a level of official recognition that most novelty roadside buildings never get. In 1997, it was added to both the National Register of Historic Places and the New York State Register of Historic Places, a formal acknowledgment that a giant duck built to sell eggs had become genuine architectural history. That recognition also cemented the Big Duck's most unusual legacy: it gave architecture criticism a word. "Duck," as a term for a building whose shape directly represents what happens inside it or what it sells, entered the academic vocabulary partly because of the Flanders landmark, a linguistic footnote most buildings never come close to earning.

Today, the Big Duck operates as a small museum and gift shop, open to the public and staffed with the kind of local memorabilia that only a nearly hundred-year-old roadside icon can accumulate: historic photographs, antique postcards, and articles chronicling both the duck's own travels and Long Island's broader roadside architecture. It is a modest operation inside an immodest building, which is more or less exactly the joke Martin Maurer was making in 1931.

Long Island has no shortage of impressive architecture, from Gold Coast mansions to modern glass towers along the waterfront. None of it draws quite the same instinctive smile as a duck-shaped egg stand that has outlived the industry it was built to serve, survived four moves, and ended up, against all odds, as a genuinely protected piece of American history.