Walls are important elements in architecture design history. Walls have been used as barriers and as structural elements as well. The biggest scale of a wall is a city wall which can protect the whole city area as a fortification--boundary. Another scale is the wall around buildings, which can define a site, a landscape, and separate a building from its surroundings. At a smaller scale, walls divide spaces in buildings. From ancient times to modern times, the wall was developed into various shapes and functions with different kinds of materials. This thesis is a study of walls of different scales and their harmonious whole. I am very interested in the city walls of Nanjing, a famous Chinese old city very close to where I was born. These city walls were built more than 200 years ago. These old walls are combined with new walls to make a space for communication and a new public attraction for the city. People can see the walls, feel the walls and then know much about the walls and architectural space. Wall gallery, visitor center and cafe/gift shop are located in this wall garden that I call "Paradise Island". / Master of Architecture