At about 9.7 million sq km, China is the world's third largest country by total area, and the second largest by land area. Its landscape is diverse, with forest steppes and deserts (the Gobi and Taklamakan) in the dry north near Mongolia and Russia's Siberia, and subtropical forests in the wet south close to Vietnam, Laos, and Burma. The terrain in the west is rugged and elevated, with the Himalayas and the Tian Shan mountain ranges forming China's natural borders with India, Nepal and Central Asia. In contrast, mainland China's eastern seaboard is low-lying and has a 14,500-km (9000 mi) long coastline (the 11th longest in the world), bounded on the southeast by the South China Sea and on the east by the East China Sea, beyond which lie Japan.
The ancient Chinese civilization—one of the world's earliest—flourished in the fertile basin of the Yellow River which flows through the North China Plain. For more than 6000 years, China's political system was based on hereditary monarchies (also known as dynasties). The first of these dynasties was the Xia (approx. 2000 BC) but it was the later Qin Dynasty that first unified China in 221 BC. The current dynasty, the Qing, was established in 1644.