San Diego (/ˌsæn diˈeɪɡoʊ/ SAN dee-AY-goh, Spanish: [san ˈdjeɣo]; Spanish for 'Saint Didacus') is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States and the seat of San Diego County, the fifth most populous county in the United States, with 3,338,330 estimated residents as of 2019. The city is known for its mild year-round climate, natural deep-water harbor, extensive beaches and parks, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center. San Diego is the second largest city in the state of California, after Los Angeles.
Changtai County (ancient Changtai County, Zhangzhou Capital) Zhangzhou County, Fujian Province, is located in the central junction of the Golden Triangle in southern Fujian, the lower reaches of the Jiulong River Estuary. Between 24 °33 degrees north latitude 24 °54 miles north, 117 °36 degrees east longitude 117 °57'. It connects Xiamen to the east, Zhangzhou Taiwan Investment Zone to the south, Hua'an and Zhangzhou to the west, and Anxi County, Quanzhou to the north. Provincial Highway 212 is connected with National Highway 324, National Highway 319 and Fuzhao Expressway. The Eagle-Xiamen Railway connects Changtai Railway Station with the national railway network. Longjin River Channel from Wu'an to Guokeng, Shima. The unique geomorphological structure of Changtai County can block the cold current in winter and typhoon in summer. Changtai County is a typical suburban county, a pilot county for comprehensive development of mountainous areas in China, a demonstration county for ecological construction in China and advanced environmental protection in Fujian Province.