"You mean the hole?" said the man standing in the doorway of his SeaTac townhome. His Hummer was parked in the driveway. He was friendly—he'd answered the door for a stranger and he was sharing his honest opinion of the four-acre sculpture next door. "It's a hole. I guess some people are really into it."

A hundred years ago, this hole was an open gravel pit. Gravel is not just gravel; it is the basic building block of development, used in a hundred different ways on every construction project. Thousands of years of restless glacial ice left the land of Western Washington—known mainly for coal and lumber—also stuffed with gravel. Geologists say some of the best gravel deposits in the country are here, and the material is pulled out of the earth from giant pits in places like DuPont (south of Tacoma).

Mining on this particular "hole" in what is now SeaTac (which incorporated in 1990) stopped in the 1940s. The pit lay abandoned on a hillside overlooking the farmland of the Kent valley with a spectacular view of Mount Rainier until 1979, when the King County Arts Commission asked an artist to turn it into an artwork. Untitled (Johnson Pit #30) by Robert Morris is probably the first permanent land-reclamation sculpture in the nation and perhaps the world, since large-scale land art, or earthwork, is like jazz or abstract expressionism—it's an American creation.

Morris bristled at the idea that an artist's role was to clean up after industry. In what became a famous speech about Johnson Pit #30, he sought to disillusion those who would "suppose that artists hired to work in industrially blasted landscapes would necessarily and invariably choose to convert such sites into idyllic and reassuring places, thereby socially redeeming those who wasted the landscape in the first place." Morris relandscaped the pit by adding pleasing concentric terraces descending to the base. But he also left rows of blackened tree stumps at the top, as a reminder of destruction.

The artist's defiant words are etched into the informational plaque at the entrance to Johnson Pit #30; the plaque also describes the site as "remote" and "contemplative." That was true in 1979. But Johnson Pit #30 now sits awkwardly between teeming, winding colonies of townhomes, all built within the last 10 years (some within the last three years, still containing their pioneer residents) and bearing names that refer to the river valley below and its mountain views: The Heights at Ridgeview, Creekside New Homes, Valley View Condominiums, River Ridge Community, Viewcrest Condos. "Total Privacy in Every Room!" is the advertisement for one unit for sale for $229,000. Seen from the top of the pit, these tightly ordered, monochromatic complexes—each with a row of flags at its entrance, like a little nation—look like toy neighborhoods. In the distance, past all the gleaming new pavement, there's one lone red barn left.

The history in this scene is so transparent that it feels like a film set. But beyond clichés about evil Hummer owners and defiant artists and disappearing farmers, what would the plot really be? And do the people here know that they're living with a renowned work of art that set out to be contentious?

"I might prefer to ask the work what it thinks of all those people building houses and living near it," the artist wrote in an e-mail response to the idea of asking the neighbors their opinions of the earthwork in their midst. Now 79 years old, Morris is a towering figure in art history; one of Seattle Art Museum's prized 20th-century possessions is his 1961 Box with the Sound of Its Own Making, a plain but finely crafted wood box with a recording of the process of the artist sawing, hammering, and sanding it into being.

Johnson Pit #30 has seen its share of those same sounds.

"When this work was built, nobody lived near it," his e-mail continued. "Even the view out into the valley was then mostly absent any industrial development. Now I believe that neither is the case. Whatever political edge the work once had, if any, has, I would guess, long ago washed out of it... As Du­champ noted some time ago, the artist makes the work and others tell him what it is. As we know, art changes over time, and the artist's intention is of no consequence to history's assessments."

Interviews with a dozen of Johnson Pit #30's neighbors who answered their doors or were caught walking to and from their cars revealed that the art is used mainly as a dog park and outdoor gym. Some owners park cars at the top and stay inside while releasing their dogs down into the pit to tire themselves out; the paths of the hilly slopes are perfect for workouts. The goats who come to clean up the blackberry brambles every year—brought in by the county arts agency that still owns and maintains the sculpture, 4Culture—make the biggest impression, not the sculpture itself, whose form is seen as either pleasant or odd or overlooked entirely. Few people had noticed the rows of tree stumps, and nobody knew what they were supposed to mean; nobody had read Morris's fighting words on the plaque.

"I don't know if people ever really consider what it is," said Bryan De Donato, a thirty­something IT consultant for Deloitte who bought his townhome—one of the few with an actual partial view of the earthwork—in 2005, when it was built. He was out on his doorstep with his new beagle puppy. "They just appreciate it for its beauty, and for hanging out and chilling."

Maybe that's the death of an earthwork: the moment it becomes like any other pocket park, just a pit-stop escape. But Johnson Pit #30 is rebuilt by its new environment. Rather than a primal shout in the woods, it's a comment spoken at close range about suburbia's blinkers. In some ways, it's louder than ever. The pit emits the sound of its own making, and reflects the clashing sounds of all human land use—if you just listen.