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.
Yinchuan, referred to as "Yin", is the capital of Ningxia Hui Autonomous region, a national historical and cultural city, and one of the important central cities in Northwest China. The military, political, economic, cultural, scientific research, transportation and financial center of the autonomous region is a comprehensive industrial city focusing on the development of light and textile industry and coordinated development of machinery, chemical industry and building materials industry. Located in the middle of Ningxia Plain, located on the western edge of Ordos in the east and Helan Mountain in the west, the Yellow River runs through the city. It is a famous historical and cultural city in China, a central city in the adjacent area of Ningxia, Inner Mongolia, Shaanxi and Gansu, and a node city of the Silk Road. it is a key economic zone for the in-depth implementation of the western development strategy. Yinchuan is an ancient city with a long history. Human beings thrived at the Shuidonggou site as early as 30,000 years ago. Yinchuan, the capital of the Xixia Dynasty in history, is a famous historical and cultural city of the country.