The Going-to-the-Sun Road is rightfully recognized as one of the most spectacular alpine highways in the world and certainly among those in the United States. The landscape is one of peerless beauty, but the road itself is an engineering masterpiece. In 1910, Glacier National Park was created in that million-acre swath of mountains, lakes, and glaciers that the great naturalist George Bird Grinnell called "the Crown of the Continent." Soon, plans...