Nanjing is the capital of Jiangsu Province in East China, a sub-provincial city, acting as the political, economic and cultural center of the province. As one of the Four Ancient Capitals, Nanjing is a vital cradle of Chinese civilization over a long stretch of time，boasting rich cultural heritage and historic relics. With a population over eight million, the city has direct jurisdiction over eleven districts including Xuanwu, Qinhuai, Gulou and Jianye districts.
Nanjing is also a major transport nucleus in the Yangtze River Delta. The Nanjingnan Railway Station is the largest railway hub in East China, and one of the five major stations on the Bejing-Shanghai High-speed Railway. Currently four metro lines are in operation, and a total of 25 lines are expected by 2030.