China, officially the People's Republic of China, is a country in East Asia. It is the world's most populous country, with a population of around 1.4 billion. Covering approximately 9.6 million square kilometers, it is the world's third or fourth-largest country by area.
The country is officially divided into 23 provinces, five autonomous regions, four direct-controlled municipalities, and the special administrative regions of Hong Kong and Macau.
China emerged as one of the world's first civilizations, in the fertile basin of the Yellow River in the North China Plain. China was one of the world's foremost economic powers for most of the two millennia from the 1st until the 19th century. For millennia, China's political system was based on absolute hereditary monarchies, or dynasties, beginning with the Xia dynasty in 21st century BCE. Since then, China has expanded, fractured, and re-unified numerous times. In the 3rd century BCE, the Qin reunited core China and established the first Chinese empire. The succeeding Han dynasty saw some of the most advanced technology at that time, including papermaking and the compass, along with agricultural and medical improvements.