The waters of Crater Lake are so blue that images without a clear indication of the skyline may actually be of the water. The background of the image at left is actually the waters of the lake. You can compare it to the image on the right, which clearly shows the water's texture. When I was taking that latter image, a bystander was prompted to ask me, "Pardon me, but what are you taking a picture of?" (the water's texture, of course). Imaged at Crater Lake National Park, OR in July 2007.