Spiral Jetty is an earthwork constructed by artist, Robert Smithson in 1970.
It's on the North shore of the Great Salt Lake in Utah should you wish to visit it.
This is the sort of thing that Smithson did. Big land sculptures. He died in a helicopter accident while overflying potential sites for a future piece.
And while I'm about it, see this geoglyph ?
It's called the Marree Man and is a modern land sculpture in a similar vein to antique works like the Cerna Abbas giant. Nobody knows who made it, but it was discovered from the air in 1998.
9 years later, photographs were taken for google earth. It's faded slightly in the decade since it's discovery.