Marvel Lake is a backcountry lake in Banff National Park. The closest campsite to the lake is Bryant Creek and it's a common stop on the way to or from Mount Assiniboine Pronvicial Park. The best views of the lake are from the Wonder Pass trail that connects Banff National Park & Mt. Assiniboine Provincial Park. The 25 km trail offers stunning mountain views and takes 9-10 hours to complete from or to ther Mt Shark helipad. We've done the hike in one day twice, but some may chose to break it up with a stay at Bryant Creek. It's pretty challenging with a heavy pack.