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.
Gansu, referred to as "Gan" or "long", is the provincial administrative region of the people's Republic of China and the capital of Lanzhou. It is located in northwest China, connecting Shaanxi to the east, Xinjiang to the west, Sichuan and Qinghai to the south, Ningxia and Inner Mongolia to the north, and Mongolia to the northwest. It is between 32 °11 miles north latitude 42 °57 miles north and 92 degrees 13 miles east longitude, covering a total area of 425800 square kilometers. The topography of Gansu is long and narrow, with complex and diverse landforms, including mountains, plateaus, flat rivers, river valleys, deserts and Gobi, surrounded by mountains and mountains, and the terrain inclines from southwest to northeast. Gansu is located in the confluence of the Loess Plateau, the Qinghai-Tibet Plateau and the Inner Mongolia Plateau. The climate types from south to north include subtropical monsoon climate, temperate monsoon climate, temperate continental arid climate and plateau.