Even after road tripping through the Swiss Alps, Montana's Going-to-the-Sun Road through Glacier National Park remains the most spectacular road that I've ever been on. For several years, I traveled this road at least once a week. It always got the blood flowing.
The construction of this road has long been hailed as a great feat of civil engineering. Certainly it was. Landscape architects' role in the planning of Going-to-the-Sun Road and other treasured scenic roads is now being honored. Check out this article in the Missoulian.