This is one of the most spectacular lakes in the whole world. It is the deepest in the U.S. with a measured depth of 1,949 feet. The water is so blue because there is hardly anything else in it – just water, according to the NPS. Boat tours, swimming, fishing, ranger talks, evening programs, camping, and other activities are offered. Explore old-growth forests or wildflower meadows, and climb mountains for great views of the lake. The national park, due to its breathtaking views, is one of the best places for RV camping.