Narrator: Bread, the staff of life. Whether baked, fried or boiled it's the basic source of nourishment for half the world. Grill it, roast it, slice it, toast it, it's a wonder that two ingredients, flour and water, can be transformed into so many shapes and tastes. White bread may still be king in the U.S., but other breads are closing in. Now, the untold story of Bread, on Modern Marvels.