Spiral Jetty is an earthwork, a work of art made for a specific place using natural materials found there, especial the earth itself.
Earthworks were one of the ways in which artists of Smithson's generation tried to move away from inherited ideas about art as an object that could be bought and sold.
as with many developments of those years, earthworks built bridges of understanding to other world traditions.
One of the most famous earthworks in the United States is the Serpent Mound, near Locust Grove, Ohio.
For almost 5,000 years, numerous Eastern American peoples built large-scale earthworks as burial sites and ceremonial centers.
Serpent Mound was long thought to have been formed by the Hopewell people during the early centuries of our era.
Recently, however, scientific methods have suggested a date of around 1070 C.E., long after the decline of Hopewell culture.
Serpent Mound contains no burials, and one archaeologist has suggested that the mound may have been created in response to a celestial event,
the sighting of Halley's comet, which flamed through the skies in 1066.