Toward the end of this century, if we don't blow ourselves up along the way, the true age of exploration and colonization will begin. Why not? We've done it all before. The story of the wanderers who challenged North and South America around 20,000 years ago is only now being reconstructed. A mere 500 years ago Columbus, Cortez, Montejo and Pizarro found and conquered the undreamed of worlds those earlier people created. Another of Earth's epic adventures...