The Grand Canyon was created primarily by the Colorado River. Around 5 to 6 million years ago, the Colorado River established its course through the region, carving deeply through the layers of the Colorado Plateau. This carving occurred as the river cut channels through rock layers while the plateau was uplifted, steepening the river's gradient and enhancing its erosive power. Over millions of years, the river, aided by its tributaries and the transportation of rocky debris during floods, deepened and widened the canyon, producing the steep, colorful walls seen today. The arid environment of the southwest also helped preserve the canyon's distinctive exposed sedimentary layers. Thus, the relentless flow and erosion caused by the Colorado River, coupled with geological uplift and tributary streams, were the main forces behind the creation of the Grand Canyon.