Switchbacks up to Tower Lake takes about 3 hours. Very steep switchbacks for about 15 minutes brings you to Rockbound Lake. There is also a scramble from this point to a ridge. A Waterfall can be seen from the back side of the lake. If you walk to the right once you get to Rockbound Lake, you will get an awesome panoramic view point.
Directions:
Location: Banff National Park: Castle Junction Area. Trailhead: Drive to the parking area on the north side of the Bow Valley Parkway 0.2 km east of Castle Junction.