Winding Colorado river beneath towering red cliffs at dusk, soft light reflecting on water. A Philip Richard Photograph

River of Million years

Another peaceful-looking "Colossus" of Nature. Stretching for thousands of kilometers, over millions of years it has carved vertiginous precipices into the flesh of the Earth to reveal the continent's 1.7 billion-year-old foundations. Today, this magnificent river barely reaches the ocean, depleted by intensive agriculture and irrigated desert golf courses.