The Monument Valley area is part of the Colorado Plateau. The floor is largely Cutler Red siltstone or its sand deposited by the meandering rivers that carved the valley. The valley's vivid red color comes from iron oxide exposed in the weathered siltstone. The darker, blue-gray rocks in the valley get their color from manganese oxide. Monument Valley was film set for many Hollywood Movies like "Forrest Gump" or "Thelma and Louise".
