Here's the underside of a "lunker structure", a manmade undercut bank where trout love to hang out. It's amazing how much I've seen the trout use these things. I've also noticed that the best trout populations I've seen are in streams where lunker structures have been installed.
Troutnut.com is a collection of pictures and information about fly fishing. Fly fishermen, fly tiers, and trout enthusiasts of all stripes can learn more about life beneath the surface of trout streams, as well as how to better imitate aquatic insects with artificial flies to catch trout. There are aquatic insect pictures, underwater pictures, landscape pictures, and a comprehensive reference to the common names of trout stream insects.