It's no accident that civilization first arose along the banks of the Tigris, Euphrates and Nile. Great rivers nourished Mesopotamia, Egypt and countless other great cultures watering crops, supplying fish, encouraging trade and creating defensive barriers.
Rivers also are the source of life for much of the planet's animal life.
Accordingly, some river journeys offer a kind of cultural time travel, inviting your mind's eye to imagine how people lived hundreds or thousands of years ago. The Rhine, with its medieval castles, and the Nile, with its Pharaonic monuments, both provide a kind of watery time warp. Other rivers allow you to experience parts of the earth as they existed when people still lived in caves. The Congo and Amazon, with their huge swaths of virgin wilderness, both fall into this category. What follows is a list of our picks for a world-class river voyage.