Cao Cao, also known as Cao Cao Tibetan Military Road, is located under the main street in the old city of Zhangzhou City, Anhui Province, with Da Dao as the center, extending to all sides to reach the outside of the city. It is the oldest and most complete underground large-scale military installation in China. Cao Cao Yunbing Road includes two parts: the watch building and the ancient tunnel. The whole tunnel is intertwined with longitude and latitude, crisscrossing; the layout is mysterious and varied; the three-dimensional distribution, the structure is complicated; the scale is grand and the project is huge. More than 8,000 meters have been found, it far exceeds the value of a complete ancient city pool retained on the ground, known as the "Great Wall underground", on June 25, 2001, Cao Cao Yunbing Road was listed as the fifth batch of key cultural relics protection units nationwide. In February 2016, the Cao Cao underground transport road scenic spot in Zhangzhou City was rated as a national AAAA-level tourist scenic spot.