Xi'an is the capital of Shaanxi province, and a sub-provincial city in the People's Republic of China. One of the oldest cities in China, with more than 3,100 years of history, the city was known as Chang'an before the Ming dynasty. Xi'an is one of the Four Great Ancient Capitals of China, having held the position under several of the most important dynasties in Chinese history, including Zhou, Qin, 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 interior 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. It is now one of the most populous built-up areas in inland China with 6,501,189 inhabitants, while the total population of the Municipality is up to 8,467,837. 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.