The quest to find the headwaters of the Nile River was the mid-19th century's equivalent to the space race. In her new nonfiction book, River of God, Candice Millard follows the story of two bitter rivals on an adventure into uncharted places to claim that prize for England. In an interview with Scott Simon on Weekend Edition Saturday, Millard spoke about the complicated legacy of the Nile's exploration and the arrogance behind "discovering" a land that has been populated for millions of years. And don't say we didn't warn you about the part where a beetle gets in someone's ear...