From fifteenth century to the twentieth, Beijing had been the home of 24 emperors, seat of government, and heart of Chinese civilization. Beijing is located in the northeastern corner of China. It is the nation's political, economic, cultural and educational center as well as the most important center for international trade and communications in China. The city limits of Beijing extend some 80km ( 50mi ), including the urban and the suburban areas and the nine counties under its administration - in other words, it's huge. Though it may not appear so in the shambles of arrival, Beijing is a place of very orderly design. Long, straight boulevards and avenues are crisscrossed by a network of lanes. Places of interest are either very easy to find if they're on the avenues, or impossible to find if they're buried down the hutongs (narrow alleys).Beijing is situated at 40 degrees north latitude and 116 degrees east longitude. It is 43 metres above sea level and 183 kilometres from the sea. Beijing covers an area of 16,800 square kilometres, 38% of it is flat land and 62% mountains.Beijing has a continental climate. Annual rainfall averages nearly 700 millimetres, most of it comes in July and August. Winter is dry and cold and has little snow, The frost-free period is 185 days. The best time to visit Beijing is May, September and October, when people enjoy bright sunny sky.