History of the Great Wall of China the three, China's chief concern since the earliest times had been Mongolia – the home of many of the country's fiercest enemies including the Xiongnu, the Xianbei, the Khitans, and the Mongols. The Gobi Desert, which accounts for two-thirds of Mongolia's area, divided the main northern and southern grazing lands and pushed the pastoral nomads to the fringes of the steppe. On the southern side (Inner Mongolia), this pressure brought the nomads into contact with China. For the most part, barring intermittent passes and valleys (the major one being the corridor through Zhangjiakou and the Juyong Pass), the North China
Taklamakan Desert to regard the Taklamakan Desert as separate and independent from the Gobi Desert region to its east. The People's Republic of China has constructed two cross-desert highways. The Tarim Desert Highway links the cities of Hotan (on the southern edge) and Luntai (on the northern edge), and the Bayingol to Ruoqiang road crosses the desert to the east. In recent years, the desert has expanded in some areas, its sands enveloping farms and villages as a result of desertification. The Golmud-Korla Railway (presently, under construction; expected completion time, 2019) will cross the Taklamakan as well. Because it lies in the