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.
Wanyuan City, which belongs to Dazhou City, Sichuan Province, gets its name because it is located in Wanqingchi and the source of Zhujiang River. it is located in the northeast of Sichuan Province, the hinterland of Dabashan Mountain, the junction of Sichuan, Shaanxi and Chongqing, and the confluence of seven counties and cities. it is the dividing line of climate between the north and south of China and the watershed of Jialing River and Han River. By the end of 2018, Wanyuan City had jurisdiction over 52 townships, covering an area of 4065 square kilometers, with a total population of 573600. Wanyuan City was established in July 1993 and has obvious geographical advantages. it is the main passage of land traffic out of Sichuan Province. It is known as the "lock key of Qinchuan". It is crossed by trunk lines such as Xiang-Yu Railway, Baomao Expressway, National Highway 210 and 347. Wanyuan City is known as "the Source of Wanbao". It is one of the three selenium-rich belts in China and the only natural selenium-rich area in Sichuan Province.