The hike to Devil's Thumb passes two epic lakes: Lake Louise and Lake Agnes and 1 waterfall. This is an easy scramble that is well worth the views. Added bonus: views of Victoria Glacier.
Park in the visitor parking lot at the Chateau Lake Louise parking lot in time for sunrise at Lake Louise...not to be missed! Then follow the pathway to the right around the lake to the Lake Agnes turnoff (well marked, with a small bronze statue at the intersection.)
The waterfall is just before a flight of stairs leading up to the teahouse and Lake Agnes. Follow the trail past the teahouse around the end of the lake and up the switchbacks. At the top, signs indicate Valley of the Ten Peaks straight ahead, and Big Beehive to the left.
Look for an unmarked pathway to the right. Stay right and go up a small (easy) rock band about 5 meters high. There is a great viewpoint just to the right before the rock band. From the top of the rock band, an easy trail contours around the mountain and then up a steep gully to the col. The view of Victoria Glacier is stunning from here. Head up to your right, where the final approach involves picking your way through a rock field to the summit and the outstanding views.