Dongshuiguan Ancient City Wall.

The story of the Dongshuiguan site covers the Dongshuiguan in the Qinhuai District of Nanjing and the Dongshuiguan site in the northeast corner of Rucheng Street in Rugao City. 12 Dongshuiguan, formerly known as Shuishangmen, is one of the water gates of the Nanjing City Wall. It is opposite to Xishuiguan and is the largest existing water gate in Nanjing. Dongshuiguan is a brick and stone structure with three floors. Each floor has 11 arch doors, a total of 33 arch doors. These arch doors are also called "Yanyue Cave". In ancient times, the upper two floors were used to place the soldiers who defended the city and store materials, and the bottom floor was used to adjust the water level of the Qinhuai River and prevent floods. Dongshuiguan integrates the water gate building and the city wall building, which is very rare in the history of Chinese architecture and can be called a masterpiece. On January 13, 1988, the Nanjing City Wall, including Dongshuiguan, was announced by the State Council of the People's Republic of China as the third batch of national key cultural relics protection units.