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.
Huainan, a prefecture-level city under the jurisdiction of Anhui Province, referred to as "Huai" and the ancient name "Zhoulai", is located in the central and northern part of Anhui Province, in the hinterland of the Yangtze River Delta and on the bank of the Huaihe River. it is known as "Zhongzhou throat, Jiangnan barrier" and "colorful Huainan". It is an important node of the urban agglomeration along the Huaihe River and the core city of Hefei metropolitan area. Huainan has a total area of 5571 square kilometers and has jurisdiction over 5 districts and 2 counties. By the end of 2016, the total population was 3.456 million. Huainan is the energy capital of China, the industrial granary of East China, the important industrial city of Anhui Province and one of the 13 larger cities of the State Council. It has obtained China's excellent tourist cities, 100 livable cities, national greening model cities, national garden cities, the first batch of national pilot smart cities, the best investment cities in China, the happiest cities in China, and Chinese idioms.