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.
Yunan District, which belongs to Yunfu City, Guangdong Province, is located in the west of Guangdong Province, the south bank of the middle reaches of the Xijiang River, Yuncheng District of Yunfu City in the east, Xinxing County and Yangchun City in the south, Luoding City and Yunan County in the west, Xijiang River and Deqing in the north, with a total area of 1184.73 square kilometers, with 7 towns under its jurisdiction and the District people's Government stationed in Liudu Town. By the end of 2017, Yun'an District had a resident population of 286300 and a total registered population of 341600. In January 1996, Yunan County was established; in September 2014, Yunan County was abolished and Yunan District of Yunfu City was established with the consent of the State Council. The topography of Yun'an District is high in the east, south and west, low in the north, dominated by hills and low mountains; located in the south of the Tropic of Cancer, the latitude is low and close to the ocean, it belongs to the subtropical humid monsoon climate with abundant rainfall.