Route 395: Eastern Sierra Nevada Mountains of California. Devil's Postpile National Monument was established in 1911 by presidential proclamation. It protects and preserves the Devils Postpile formation, the 101-foot high Rainbow Falls, and pristine mountain scenery. The Devils Postpile formation is a rare sight in the geologic world and ranks as one of the world's finest examples of columnar basalt. Its columns tower 60 feet high and display an unusual symmetry. MODEL RELEASED.