The Front Range of the Rocky Mountains provides a dramatic backdrop for metropolitan Denver, located on the western margin of the Great Plains. The landform change from the plains of the Colorado Piedmont to the faulted eastern slopes of the Rocky Mountains is abrupt. The north-flowing South Platte River, winding through the center of downtown Denver, and its floodplain are apparent. Visible are metropolitan street grid patterns; several lakes and reservoirs; and, to the northeast, runways of the new Denver International Airport surrounded by rectangular, cultivated fields to the east and northeast.