Massive forces have transformed our nation over billions of years, sculpting and shaping it into the breathtaking landscape we know today. All around us, natural wonders abound, from South Dakota's badlands to Yellowstone's boiling cauldrons to West Virginia's stunning spine of quartzite. See them all from towering heights on this cross-country voyage over America's most astonishing natural sights, formed inch-by-inch over a period of time.