America may be the land of the free, but the two leading contenders for the title of “great American novel” actually take place on the water. For Melville, the ocean contained all of humanity’s great secrets (and metaphors); but for Twain, it was the water itself that was the key. In Adventures of Huckleberry Finn, the river is both the setting of the novel and its central theme. And the fact that it also paved the way (so to speak) for the American road movie is just an added bonus.