When I am traveling across this country (and others), I pay close attention to the roads and the rivers. The roads, of course, are of human design, easing our progress across the landscape and offering interconnection with a maze of routes.
Rivers are nature's highways, fed by numerous tributaries and flowing toward the sea or to a basin lake or sink. Used by wildlife and early humans as natural routes, they remain important today as a means of transportation. But while early man understood their significance with respect to the lay of the land, modern human travelers generally accept them as natural impediments that must be crossed by a bridge or ferry.
Those of us who are interested in geography know that rivers and their tributaries explain the topography. We recognize when we pass from one watershed to another and come to appreciate the vast networks that feed the major waterways. Mountains are surely beautiful and inspiring but streams have sculpted them and define their place in the overall landscape.