Covering approximately 9.6 million square kilometres, China is the world's second-largest country by land area, but only the third or fourth-largest by total area, dependent on whether the surface areas of various inland bodies of water such as the Great Lakes are included in the total area of a country.[g] China's landscape is vast and diverse, ranging from forest steppes and the Gobi and Taklamakan deserts in the arid north to subtropical forests in the wetter south. The Himalaya, Karakoram, Pamir and Tian Shan mountain ranges separate China from South and Central Asia. The Yangtze and Yellow Rivers, the third- and sixth-longest in the world, run from the Tibetan Plateau to the densely populated eastern seaboard. China's coastline along the Pacific Ocean is 14,500 kilometres (9,000 mi) long, and is bounded by the Bohai, Yellow, East and South China Seas.
The ancient Chinese civilization – one of the world's earliest – flourished in the fertile basin of the Yellow River in the North China Plain. For millennia, China's political system was based on hereditary monarchies, known as dynasties, beginning with the semi-mythological Xia of the Yellow River basin (c. 2000 BCE). Since 221 BCE, when the Qin Dynasty first conquered several states to form a Chinese empire, the country has expanded, fractured and been reformed numerous times. The Republic of China overthrew the last dynasty in 1911, and ruled the Chinese mainland