Few lands are untouched by the power of a stream. Even the driest regions can hold traces of ephemeral river runs. Rivers create their own channels, gathering rain or snow and ice melt that runs off the land and bearing it downhill by force of gravity to the sea. The journey makes rivers the unsurpassed carvers of Earth, cutting canyons and valleys and depositing sediments as fertile soils. By nature, they wind—the most efficient way for water to travel. Rivers and lakes store less than half a percent of Earths fresh water, but they are the lifelines of human history—where people settled, farmed, traded, built cities, explored. A new chapter in river mapping reveals the true intricacies of river flow as headwaters feed consecutively larger tributaries that surrender their waters to the mainstream. Most major rivers are now yoked with dams and reservoirs, but on this map, rivers run free. Ten Longest River s 1. Nile (Africa) 4,400 miles 2. Amazon (South America) 4,150 miles 3. Y