Photos of Cao Cao Military Transport Tunnel

<p>The Cao Cao Military Transport Tunnel under the main streets of the old city of Bozhou, with Dayushou as the center, extends in all directions to the city outside. The entire tunnel is intertwined, varied and huge, known as the "Underground Great Wall," far exceeding the value of a complete ancient city retained on the ground. The relics unearthed from the tunnel include bullets, iron knives, porcelain, inkstones and others of the Han, Tang and Song Dynasties, which are of great significance to the study of ancient Chinese military architecture, military tactics and of Cao Cao's military approach.</p>