Guangzhou is also known as Yangcheng and Huacheng. Guangzhou, referred to as Yangcheng and Huacheng for short, is a prefecture-level city under the jurisdiction of Guangdong Province, the capital of Guangdong Province, a sub-provincial city, a national central city, a megacity, a core city of Guangzhou metropolitan area, an important national central city, an international business center and a comprehensive transportation hub approved by the State Council. By 202 1, there will be 1 1 districts in the city, with a total area of 743,440 square kilometers, permanent population18,870,600, urban population16,263,600, and the urbanization rate is 86.46%. Historical Development From Qin and Han Dynasties to Ming and Qing Dynasties, Guangzhou has been an important port city for China's foreign trade for more than 2,000 years. It is the starting point of China's Maritime Silk Road. According to the Records of Geography of the New Tang Dynasty, in the Tang Dynasty, this maritime "Silk Road" was called "Guangzhou Tonghai Postal Road". Its voyage starts from Guangzhou, passes through the South China Sea and the Indian Ocean, reaches the port of Basra, and reaches the coast south of the equator in East Africa. This is the longest ocean route in the world before16th century. By the Tang and Song Dynasties, Guangzhou had developed into a world-famous oriental port, and established the first institution in China to manage foreign trade affairs-the Municipal Ambassador; During the Ming and Qing Dynasties, Guangzhou was a particularly open port. For a long time, it was the only foreign trade port city in China. After the Opium War, China and Britain signed the treaty of nanking, which forced the opening of five trading ports in Guangzhou, Shanghai, Ningbo, Fuzhou and Xiamen, ending the one-stop trade in Guangzhou.