Mountain City Walking Introduction: Chongqing was once the capital of the ancient Ba Kingdom and the Ba County of the Qin Dynasty. However, until around 1891, when it was opened as a port, it was still just a feudal city with an area of ​​less than 5 square kilometers and a population of less than 250,000. In modern times, Chongqing, which is located inland, took advantage of its location and geography, seized the opportunities given by history, and gradually completed its own urban modernization process amidst the impact of colonization and the flames of war.