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.
Baoshan District, located in the north of Shanghai, is divided into two parts: land and island. On land, it is bordered by the Yangtze River in the northeast, Huangpu River in the east, Yangpu, Hongkou, Jing'an and Putuo in the south, Jiading District in the west, Taicang City in Jiangsu Province in the northwest, and Yunzaobang in the middle of China. Wusong Bridge, Yunchuan Road Bridge, Jiangyang Road Bridge and Tangqiao Bridge span it. The two islands of Changxing and Hengsha lie in the south branch of the Yangtze River Estuary from west to east. They are 56.15km long from east to west and 23.08km wide from north to south, covering an area of 424.56 square kilometers. Located at the confluence of the Huangpu River and the Yangtze River, Baoshan can be called the "waterway gateway" of Shanghai. It connects more than 400 ports in 164 countries and regions by sea. The throughput of containers accounts for more than 70% of Shanghai Port.