There are still many unanswered questions about Chinese Emperor Qin Shi Huang's Terracotta Army. Using face recognition technology, painstaking archaeological research, and interviews with craftsmen who build life-size replicas today, experts unravel the mysteries of the two-metre tall, 300kg pottery figurines found in 1974 in the tomb of China's first Qin Dynasty ruler, revealing why they were one of the most fascinating and mysterious finds of the last century.