Cuu vi Than Cong (nine holy cannons) is a famous landmark of Hue and a symbol of the Nguyen Dynasty grandeur.
The nine majestic cannons located in front of the Imperial Citadel, were manufactured in 1803, and were considered masterpieces of bronze art. Four cannons were named after four seasons spring, summer, autumn and winter and the other five were named after the Wu Xing (Five Elements) metal, wood, water, fire, and earth. In 1826, Gia Long Emperor bestowed the little of Than Oai Vo Dich Thuong Tuong Cong (Undefeated Super Power of Senior General) upon the nine cannons.