Goldsworthy developed a vision of a sculptural work spanning the North American continent while walking on the grounds of Greenwood Park. Looking back at the museum, he was inspired by the local Lannon limestone that Eliel Saarinen used to create the Art Center’s first building, which, despite Iowa’s current distance from the ocean, contains fossils of ancient sea creatures from an earlier epoch. Goldsworthy conceived of an imaginary line through the continent, composed of three points, radiating from the center of the country to the East and West coasts. At each of these locations, he built a cairn, a stack of stone constructed as a memorial or landmark, from the same Iowa limestone. In Des Moines, the project's center point, he created a sculpture that consists of a cairn with three massive boxlike walls arrayed to the east, west, and south. Each wall has a teardrop-shaped cavity specifically sized to fit one of the three cairns that compose the continent-spanning piece. The center wall has a chipped-out section the exact size of the cairn at the museum. The east facing wall points toward the Neuberger Museum of Art in Harrison, New York, while the west facing wall points towards La Jolla, California and the San Diego Museum of Art, the other locations at which Goldsworthy installed cairns. The size of each opening mirrors the size of the cairn installed at each location. Stone steps invite entry into the chipped-out spaces in the walls, wherein one experiences the sensation of the work encircling and housing the body. All the elements of Goldsworthy’s piece were hand built using dry stone construction, a process where the stones are not joined with mortar, but rather carefully shaped and balanced on top of each other.  

To emphasize the temporary nature of these structures, Goldsworthy constructed a set of more ephemeral cairns prior to the more permanent installations. These temporary works would serve as a memory, showing the eventual impermanence of the more massive cairns that would follow. One such temporary cairn was installed near Grinnell College and became known as the Prairie Cairn.  Similar temporary cairns were built near the water on the east and west coasts. These costal cairns washed away within a few weeks.