Nanjing City Walls

Ancient Chinese emperors, through out China's long history had been fortifying their kingdoms with thick stone walls to ward off enemies from other states. These fortresses are present in some ancient cities like Nanjing which used to be the capital. Many parts of the ancient walls have been rebuilt and restored very recently however, and may not reflect the exact materials used in the construction of the original walls. Even then, rebuilding miles of massive structures is a feat simple folks can only wonder.