The boundaries of Asia have always been prone to change and debate. As the leaders have changed, the divisions and subdivisions have changed as well. The mainland has always been referred to as China Proper. There are many countries surrounding China, and the dynasties have frequently pushed outward and included them into China. For example, the Qing dynasty expanded its rule into Mongolia and Tibet. The Great Wall has served to be a general boundary of China today, as well as one of the most stunning and recognizable landmarks.