The Ming City Wall of Nanjing, once the capital of China for six dynasties including Ming. The wall was built during Ming Dynasty (1368-1644 AD). The quality of the wall was guaranteed first by the high quality of bricks manufactured in and contributed from the surrounding provinces. Each brick has a seal bearing the name and location of the brick-kiln, and time and supervisor of the production. This is one of the key reasons why this wall has lasted so long. on the left is the Xuanwu Lake, and on the far end is the Zijin (Purple Gold) Mt., the landmark of Nanjing.