The highway's curve mirrors the curves of these Nebraska sandhills, one after another, for about 19,300 square miles of grass-stabilized sand dunes all across western Nebraska. In many places, as you cross the top of a towering dune and look into the valley, you will see wetlands from the Ogallala Aquifer breaching the surface and providing homes for birds and aquatic life and stopover places for migrating birds. The red cedar trees are invasives; most of this area is virgin prairie.