Nanjing, formerly romanized as Nanking and Nankin, is a city situated in the heartland of the lower Yangtze River region in China, which has long been a major centre of culture, education, research, politics, economy, transport networks and tourism. It is the capital city of Jiangsu province of People's Republic of China and the second largest city in the east China region, with acreage about 6600 square kilometers and a total population of 8,230,000. The inner area of Nanjing enclosed by the city wall is Nanjing City (南京城), with acreage of 55 km2, while Nanjing Metropolitan Region includes surrounding cities and areas, with acreage over 60 thousand km2 and population over 30 million.
Nanjing has a prominent place in Chinese history and culture, having served as the capital of various Chinese dynasties, kingdoms and republican governments dating from the 3rd century CE to 1949. The city has a number of other names, and some historical names are now used as names of districts of the city; among them there is the name Jiangning or Kiangning (江寧, literally "Yangtze's Peace"), whose former character Jiang (江, River) is the former part of the name Jiangsu and latter character Ning (寧, simplified form 宁, Peace) is the short name of Nanjing. When it was the capital of a state, for instance during the ROC, Jing (京) was adopted as the abbreviation of Nanjing. It first became a Chinese national capital as early as the Jin dynasty, and the name Nanjing was officially designated for the city during the Ming dynasty, about a thousand years later. Nanjing is particularly known as Jinling or Ginling (金陵, literally "Gold Mausoleum") and the old name has been used since the Warring States period in the Zhou Dynasty.
Located in Yangtze River Delta area and the center of east China, Nanjing is home to one of the world's largest inland ports. The city 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 been ranked 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 Honour of China, Special UN Habitat Scroll of Honour Award and National Civilized City. Nanjing boasts many high-quality universities and research institutes, with the number of universities listed in 100 National Key Universities ranking third, including Nanjing University and Southeast University. The ratio of college students to total population ranks No.1 among large cities nationwide. Nanjing is one of the top three Chinese scientific research centers, especially in the chemical sciences, according to the Nature Index.
Nanjing, one of the nation's most important cities for over a thousand years, is recognized as one of the Four Great Ancient Capitals of China. It has been one of the world's largest cities, enjoying peace and prosperity despite wars and disasters. Nanjing served as the capital of Eastern Wu, one of the three major states in the Three Kingdoms period (211–280); the Eastern Jin and each of the Southern Dynasties (Liu Song, Southern Qi, Liang and Chen), which successively ruled southern China from 317–589; the Southern Tang, one of the Ten Kingdoms (937–76); the Ming dynasty when, for the first time, all of China was ruled from the city (1368–1421); and the Republic of China (1927–37, 1945–49) prior to its flight to Taiwan during the Chinese Civil War. The city also served as the seat of the rebel Taiping Heavenly Kingdom (1851–64) and the Japanese puppet regime of Wang Jingwei (1940–45) during the Second Sino-Japanese War. It suffered appalling atrocities in both conflicts, including the Nanjing Massacre.
Nanjing has served as the capital city of Jiangsu province since the establishment of the People's Republic of China. It boasts many important heritage sites, including the Presidential Palace and Sun Yat-sen Mausoleum. Nanjing is famous for human historical landscapes, mountains and waters such as Fuzimiao, Ming Palace, Chaotian Palace, Porcelain Tower, Drum Tower, Stone City, City Wall, Qinhuai River, Xuanwu Lake and Purple Mountain. Key cultural facilities include Nanjing Library, Nanjing Museum and Art Museum.