To defend himself in the afterlife, the First Emperor of China, Qin Shi Huang, was buried in a vast mausoleum accompanied by around 9,000 life-sized terracotta statues. With exclusive access to groundbreaking new research, NOVA investigates the secrets of how and why the astonishing figures were made and the technology behind the still lethal and highly-advanced crossbows, spears, and swords carried by the clay warriors.