Phoenix (/ˈfiːnɪks/ FEE-niks; Navajo: Hoozdo; Spanish: Fénix or Fínix,[citation needed] Walapai: Banyà:nyuwá) is the capital and most populous city of the U.S. state
of Arizona, with 1,608,139 residents as of 2020. It is the fifth-most populous city in the United States, and the only U.S. state capital with a population of more than one million residents.
Phoenix is the anchor of the Phoenix metropolitan area, also known as the Valley of the Sun, which in turn is part of the Salt River Valley. The metropolitan area is the 11th largest by population in the United States, with approximately 4.85 million people as of 2020. Phoenix, the seat of Maricopa County, has the largest area of all cities in Arizona, with an area of 517.9 square miles (1,341 km2), and is also the 11th largest city by area in the United States. It is the largest metropolitan area, both by population and size, of the Arizona Sun Corridor megaregion.
Xining, known as Qingtang City, Xiping County and Shanzhou in ancient times, is the capital of Qinghai Province, the political, economic, scientific and educational, cultural, transportation and communication center of Qinghai Province, and an important central city in the northwest region approved by the State Council. By 2019, the city had jurisdiction over five districts and two counties, with a total area of 7660 square kilometers, a built-up area of 129 square kilometers, a resident population of 2.3711 million, an urban population of 1.7098 million, and a urbanization rate of 72.1 percent. Xining is located in the eastern part of Qinghai Province, swimming in the river valley basin in the Huangshui River. It is the eastern gateway of the Qinghai-Tibet Plateau and the necessary place for the ancient "Silk Road" South Road and "Tangbo Ancient Road". It has been the northwest traffic road and military important place since ancient times. Known as the "key to the West Sea" and the throat of the sea, it is one of the high-altitude cities in the world and is also the State Council.