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.
Pu'an County, which belongs to the Buyi and Miao Autonomous Prefecture in southwestern Guizhou Province, is located in the southwest of Guizhou Province, adjacent to Qinglong County to the east, Xingren County and Xingyi City to the south, Panzhou City in Liupanshui City to the west, and Liuzhi Special Zone in Liupanshui City to the north. In 2015, the county has a total area of 1454 square kilometers, with jurisdiction over 2 streets, 8 towns and 2 townships, and Panshui Street where the county seat is located; it has an area of 254000 mu of arable land and a total population of 331900, inhabited by more than ten ethnic groups such as Han, Miao and Buyi. In 2014, Pu'an County completed a GDP of 5.015 billion yuan. There are 46 rivers in Pu'an County, the theoretical reserve of water energy is 270000 kilowatts, and there are 28 kinds of mineral deposits such as coal, gold, iron, silicon, lead and zinc. Puan County has the oldest in the world.