Kunming (Chinese: 昆明, pinyin: Kūnmíng; UN/LOCODE: CNKMG) is the capital and largest city of Yunnan (云南) Province in Southwest China. It was known as Yunnan-Fou (云南府, Yúnnánfǔ) until the 1920s. A prefecture-level city, it is the political, economic, communications and cultural centre of Yunnan, and is the seat of the provincial government. It is also home to several universities, museums, galleries and other important economic, cultural, and educational institutions. The headquarters of many of Yunnan's large businesses are in Kunming as well. It was important during World War II as a Chinese military center, American air base, and transport terminus for the Burma Road. Located in the middle of the Yunnan-Guizhou Plateau, Kunming is located at an altitude of 1,900 m above sea level and at a latitude just north of the Tropic of Cancer. It covers an area of 21,473 square kilometres (8,291 sq mi) and its urban area covers 2,081 km² (803 sq mi). Kunming has population of 6,432,212 including 3,055,000 in the urban area and is located at the northern edge of the large Lake Dian, surrounded by temples and lake-and-limestone hill landscapes.