Beautiful Lake Louise (in Banff National Park, near the southern terminus of the Icefields Parkway and 110 mi/175 km northwest of Calgary) is a stunning, turquoise-blue lake fed directly by the dramatic Victoria Glacier at one end.
Be aware that ice may be covering Lake Louise through May and possibly even June. If so, you won't be able to enjoy its remarkable color and famous reflection of the surrounding mountains.
Almost as famous as the lake is the Chateau Lake Louise, a deluxe resort that stands on one shore. Like the Banff Springs Hotel, it was built by the Canadian Pacific Railway in the late 1800s. If you're staying there, be sure to get a room overlooking the lake (they aren't cheap, but none of the rooms at the hotel are). If you're just there for the day, splurge on lunch in the Fairview Bar & Restaurant, which offers views of the water.
Unless you are staying or dining at the hotel, you may not get to see much of the chateau's interior: Many areas are off-limits to nonguests because of the large numbers of day-tripping gawkers who used to crowd the lobbies. A shopping arcade is open to day visitors, however.
Try to stay at least one night in the area so you can take advantage of some of the opportunities for outdoor recreation (there are several fine places to stay near the lake aside from the Chateau Lake Louise). From the terrace of the chateau, hiking and packhorse trails fan out to various historic teahouses. One sits on the shore of nearby Lake Agnes, and another is at the toe of the Plain-of-the-Six Glaciers.
Near the Chateau is Moraine Lake, a visual treat in its own right and site of the trailheads for Larch Valley, Sentinel Pass and Eiffel Lake. They are all particularly stunning in the fall when the larch trees shellac the slopes with shades of gold. To access Moraine Lake, follow the winding road that begins near Chateau Lake Louise. (The road is closed in winter.)
Though the majority of visitors to Lake Louise arrive in the summer, when things can become quite crowded, downhill skiing attracts cold-weather tourists. The Lake Louise Ski Area is one of Canada's most spectacular: There's a view of the glorious glacial lake from the slopes. More than 4,200 acres/1,700 hectares of skiable terrain are spread across several mountain faces, with several lengthy runs. The Front Side has lots of slopes geared to intermediate and beginning skiers, and advanced skiers and hardy snowboarders should head to the Back Bowls.