Beijing is China's third largest city in terms of population, after Chongqing and Shanghai. It is a major transportation hub, with dozens of railways, roads and expressways passing through the city. It is also the focal point of many international flights to China. Beijing is recognised as the political, educational, and cultural centre of the People's Republic of China, while Shanghai and Hong Kong predominate in economic fields. Beijing is one of the Four Great Ancient Capitals of China, having hosted the seat of government from Yuan Dynasty in 1264 to the present, with the exception of a period of time during early Ming (1368-1420) and during the period from 1928-1949. Beijing will host the 2008 Summer .