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.
Wanshan District, which belongs to Tongren City, Guizhou Province, is the main urban area of Tongren City. It is dominated by karst karst landforms and belongs to the mid-subtropical monsoon humid climate. In November 2011, the State Council approved the cancellation of Tongren City at the prefecture level and the establishment of Wanshan District. It now covers an area of 842 square kilometers with a total population of 270000 and has jurisdiction over 11 townships (towns and streets). With convenient transportation, Wanshan is an important transportation hub for Sichuan and Chongqing to reach the sea from the east, Shanghai and Hangzhou to the west to Guizhou and Yunnan, Beijing and Tianjin to the south to Guiqiong, Guangzhou and Shenzhen to the north to Shaanxi and Gansu. The three expressways of Shanghai, Kunming, Hangzhou and Rui pass through the border. Hunan-Guizhou Railway, Zhu-Liu double Line and Yu-Huai double Line are surrounded by three railways, reaching Tongren Railway Station, Tongren High-speed Railway Station and Zhusha Guzhen Station in 10 minutes, and Dalong, Yuping, Xinhuang Railway Station and Shanghai-Kunming High-speed Railway Station Tongren in 30 minutes.