The Colorado River leaves Moab, Utah through a passage of canyon called "The Portal". From there, it glides placidly through the softer sandstones that make the famous sprawling upside-down geography of Canyonlands National Park and Dead Horse Point. Even the collision of two of the largest river systems in the Western United States occurs with surprisingly little sound or commotion. But immediately downstream of that confluence, at twice its previous size, the Colorado River enters the aptly named Cataract Canyon.
