North America – a continent of daring and drastic extremes, of conquerors and visionaries, of untamed wilderness and feats of human engineering – and its rivers are a fascinating example. The U.S. has the largest dams, the deepest locks, the longest canals and aqueducts in the world. Rivers have been modified and manipulated, forced into man-made paths, controlled by computers; even their flow has been reversed. World famous cities owe their names to these rivers: Miami, Detroit and Los Angeles - yet today they are hardly remembered.