China was the most isolated of the river valley civilizations. Long distances and physical barriers separated China from Egypt, the Middle East, and India. This isolation contributed to the Chinese belief that China was the center of Earth and the sole source of civilization. These beliefs in turn led the ancient Chinese to call their land Zhongguo (jahng gwoh), or the Middle Kingdom.
The Huang River is also called the Yellow River. Its color comes from the loess, or soil, that settles in the water. Great amounts of loess displace the water, causing the river to rise and flood.
To the west and southwest of China, brutal deserts and high mountain ranges—the Tian Shan (tyen shahn)and the Himalayas—blocked the easy movement of people. To the southeast, thick rainforests divided China from Southeast Asia. To the north awaited a forbidding desert, the Gobi. To the east lay the vast Pacific Ocean.
Despite these formidable barriers, the Chinese did have contact with the outside world. They traded with neighboring people and, in time, Chinese goods reached the Middle East and beyond.
More often, the outsiders whom the Chinese encountered were nomadic invaders. To the Chinese, these nomads were barbarians who did not speak Chinese and lacked the skills and achievements of a settled society. Nomads conquered China from time to time, but they were usually absorbed into the advanced Chinese civilization.
As the Chinese expanded over an enormous area, their empire came to include many regions.