The ruins of the city wall of Dadu in the Yuan Dynasty.

The ruins of the capital city wall of the Yuan Dynasty are located in Chaoyang District and Haidian District of Beijing. They are the ruins of the outer walls of the capital city of the Yuan Dynasty. They were mainly built with rammed earth and are commonly known as "Tucheng". The city wall was built in the fourth year of the reign of Emperor Kublai Khan of the Yuan Dynasty (1267) and was completed in the nineteenth year of the reign of Emperor Shun of the Yuan Dynasty (1359). In order to strengthen the defense, urns and suspension bridges were built at the eleven gates of the capital city. After the establishment of the Ming Dynasty, the original Yuan Dynasty city wall was wrapped with bricks, and the northern city of the Yuan Dynasty was moved 1 kilometer south to rebuild the Ming Dynasty city wall. Therefore, the northern sections of the North City Wall and the West City Wall of the Yuan Dynasty have been preserved. The city walls were all made of rammed earth. In order to strengthen the city walls, "Yongding pillars" (vertical pillars) and "紴 pillars" (horizontal beams) were used in the rammed earth. The architectural form, construction methods and careful and rigorous planning and design of the Yuan Dadu City Wall have become important physical data for studying Yuan Dynasty architecture and Yuan Dynasty urban construction projects as well as the history of Beijing's urban development.