Beacon towers
Beacon towers, also known as beacon, ancient Chinese strategic buildings, generally built at the insurance or traffic arteries. When the enemy is found, an alarm is issued: ▪ During the daytime, the firewood is filled with feces, and the smoke is released to express the message. ▪ At night, dry wood with sulfur and saltpeter is burned to make the fire clear, Know the war occurred, send troops to help. "Wu Jing total" in mind: "Tang law: where the side of the city waiting for thirty miles in a Feng, to be in the mountains Gao Jun Department, if the mountains isolated, terrain inconvenience, then unlimited, to Feng Feng Feng ; If the border, the flames of the outer fortress. Since the Shang and Zhou to China has set up a beacon on the border, the most famous event is Zhou You Wang's "flames opera princes." ...