The Spiral Jetty is a site specific installation made by Smithson in the 70's. It was a huge debate then and some may consider it even now to not be art. I, for one, think it's fantastic. (Though my love for it may be a bit bias: B and I took a trip there on one of our very first dates.)
If you live in Utah or ever visit Utah, I highly suggest checking it out.
I'll no doubt report tomorrow with an overwhelming amount of photos :)