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.
Maanshan, referred to as "Ma", is a prefecture-level city in Anhui Province, located in the eastern part of Anhui Province and the confluence area of Jiangsu and Anhui Province. it is a member city of Hefei Metropolitan area, Nanjing Metropolitan area, member cities of Yangtze River Delta Urban agglomeration, cities along Yangtze River Economic Belt and Wanjiang City Belt to undertake industrial transfer demonstration area; it has jurisdiction over 3 districts and 3 counties with a total area of 4049 square kilometers. In 2018, the resident population was 2.337 million. Ma'anshan, which straddles the Yangtze River and borders Nanjing, has been known as "Jinling barrier and Jiankang lock key" since ancient times. As early as the six dynasties, many famous princes and virtuous scholars lingered in Maanshan, leaving many monuments and cultural relics. It has successively won the national civilized cities, national public cultural service standardization construction pilot cities, national science and technology pilot cities, southern Anhui international tourism culture demonstration zone, and the first batch of countries.