In 1974, a group of farmers digging a well in central China stumbled upon a buried figure. It turned out to be one of an estimated 7,000 life-sized terra cotta warriors in an underground tomb complex. The warriors and a host of other figures were created for China's first emperor, Qin Shihuangdi. NPR host Guy Raz drops by the National Geographic Museum in Washington, D.C., to see an exhibit of the figures.