You just can't drive the Trans-Canada and not make a stop at Lake Louise. It's the definitive, textbook example of an idyllic mountain lake. And it's at exactly the point where you have to stop for a rest anyway when heading west from Calgary. Not surprisingly, it's also the definitive, textbook example of a smoothly run tourist trap.
This is seriously rugged terrain, in the heart of the Canadian Rockies. The valley is comfortable, but the slopes are harsh; even the hardiest of trees call it quits about halfway up.