Carved from cliffs and canyons, buried in desert rock and sand are pieces of the ancient past that beckon thousands of visitors every year to the American Southwest. Whether Montezuma Castle or a chunk of pottery, these traces of prehistory also bring archaeologists from all over the world, and their work gives us fresh insight and information on an almost day-to-day basis. Who hasn't dreamed of boarding a time machine for a trip into the past? This...