The document describes a journey down a river from its source to the sea. It divides the river into three sections - the upper, middle, and lower courses. The upper course is narrow with rapids and waterfalls as the river flows over rocky ground. The middle course widens and slows as the ground becomes smoother. The lower course nears the end, where the river meets the sea and deposits sediment to form deltas and estuaries. Key features of rivers mentioned include tributaries, meanders, oxbow lakes, flood plains, and confluences.