Rivers shape the landscape over time through erosion, transportation, and deposition of sediment. As a river flows, it erodes the land by picking up and carrying away rock particles and soil. This erosion can create valleys, canyons, and riverbanks. The sediment that the river carries is then transported downstream, where it can be deposited in new areas, forming features like river deltas and alluvial plains. Over centuries, the continuous process of erosion, transportation, and deposition by rivers can significantly alter the landscape, carving out new landforms and reshaping the terrain.