I'd never come across it before either and I think it is is quite a groovy thing, despite getting it wrong (for me) on so many counts. I find this image from that website epic, righteous and strangely moving.

http://columbiariverimages.com/Images04/stonehenge_columbia_river_2004.jpg

We were lucky enough to drive around Washington State for 3 weeks, about 20 years ago. We took the mail-boat 2-day trip down Hell's Canyon to the Salmon River and then drove on through what they call Chief Joseph's Land. A very moving experience when you contemplate how he & his people were driven from their homeland of Wallowa Valley.