Tianjin is a metropolis in northern China and one of the five national central cities of the People's Republic of China. It is governed as one of the four direct-controlled municipalities of the PRC, and is thus under direct administration of the central government. Tianjin borders Hebei Province and Beijing Municipality, bounded to the east by the Bohai Gulf portion of the Yellow Sea. Part of the Bohai Economic Rim, it is the largest coastal city in northern China.In terms of urban population, Tianjin is the fourth largest in China, after Shanghai, Beijing, and Guangzhou. Tianjin is a dual-core city, with its main urban area located along the Hai River, which connects to the Yellow and Yangtze Rivers via the Grand Canal; and Binhai, a New Area urban core located east of the old city, on the coast of Bohai Sea. As of the end of 2010, around 285 Fortune 500 companies have set up base in Binhai, which is a new growth pole in China and is a hub of advanced industry and financial activity. Since the mid-19th century, Tianjin has been a major seaport and gateway to the nation's capital.