For a full description of physical geography, see the CIA factbook entry on China.
The country has one of the world's oldest civilisations, which has been maintained continuously since the third century BC, despite dynastic changes and the empires set up by Mongols, Manchus and Japanese.
The country has had numerous scientific and technological acheivements, most notable amongst which are the "Four Inventions", the compass, paper, printing and gunpowder.
Interaction with the west started officially in the early Han Dynasty (2nd century BC), though there were informal contacts earlier than this. The main traffic was along the Silk Road , the main influences of which were the introduction of silk and many other Asian products to the West, and the introdcution of Buddhism to China and thence to Japan. The contact reached a peak during the Tang Dynasty (7th-10th centuries AD) with a brief resurgence with the Mongol Empire (12th-13th centuries AD) created by Genghis Khan, when Marco Polo visited. The trade then subsided as the ocean routes became easier, and withered totally under the isolationist policies of the Ming and Qing Dynasties.
The current century has seen vast changes in China, with transition from an imperial semi-feudal system to a modern socialist state, via the upheavals of the intermediate republican period. The period has witnessed some huge natural catastrophes; floods, droughts, typhoons and earthquakes have caused great loss of life. These problems are gradually being overcome, as the People's Republic has raised its sights towards the standards of developed countries, and the current policies of pursuing a socialist market economy start to pay off.