Nanjing has always been one of China's most important cities. It served as the capital of China during several historical periods and is recognised as one of the Four Great Ancient Capitals of China. Nanjing was the capital of the Republic of China before the Chinese Civil War in 1949. Nanjing is also one of the fifteen sub-provincial cities in the People's Republic of China's administrative structure, enjoying jurisdictional and economic autonomy only slightly less than that of a province. Nanjing has long been a national center of education, research, transport networks, and tourism. The city will host the 2014 Summer Youth Olympics.With an urban population of over five million (2006), Nanjing is the second largest commercial center in the East China region, after Shanghai. It has been ranked fourth by Forbes magazine in its listing of "2008 Top 100 Business Cities in Mainland China", seventh in the evaluation of "Cities with Strongest Comprehensive Strength" issued by the National Statistics Bureau, and second in the evaluation of cities with most sustainable development potential in the Yangtze River Delta. It has also been awarded the title of 2008 Habitat Scroll of Honor of China, Special Award of UN Habitat Scroll of Honor and National Civilized City.