Xi'an; Chinese: 西安; pinyin: Xī'ān), formerly romanized as Sian, and also known as Chang'an; Chinese: 長安; pinyin: Cháng'ān) before the Ming dynasty is the capital of Shaanxi Province, People's Republic of China. It is a sub-provincial city located in the center of the Guanzhong Plain in Northwest China. One of the oldest cities in China, Xi'an is the oldest of the Four Great Ancient Capitals, having held the position under several of the most important dynasties in Chinese history,including Western Zhou, Qin, Western Han, Sui, and Tang. Xi'an is the starting point of the Silk Road and home to the Terracotta Army of Emperor Qin Shi Huang.
Since the 1990s, as part of the economic revival of inland China especially for the central and northwest regions, the city of Xi'an has re-emerged as an important cultural, industrial and educational centre of the central-northwest region, with facilities for research and development, national security and China's space exploration program. Xi'an currently holds sub-provincial status, administering 9 districts and 4 counties. As of 2015 Xi'an has a population of 8,705,600 and the Xi'an-Xianyang metropolitan area has a population of 13,569,700. It is the most populous city in Northwest China, as well as one of the three most populous cities in Western China. According to a July 2012 report by the Economist Intelligence Unit, it was recently named as one of the 13 emerging megacities, or megalopolises, in China. The report pinpoints and highlights the demographic and income trends that are shaping these cities' development.