Xiamen, formerly romanized as Amoy, is a sub-provincial city in southeastern Fujian, China, beside the Taiwan Strait. It is divided into six districts: Huli, Siming, Jimei, Tong'an, Haicang, and Xiang'an. Altogether, these cover an area of 1699.39km2 with a population of 3,531,347 as of 2010. The urbanized area of the city has spread from its original island to include parts of all six of its districts, with a total population of 1,861,289. This area connects to Quanzhou in the north and Zhangzhou in the west, making up a metropolis of more than five million people. The Jinmen or Kinmen Islands administered by the Republic of China lie less than 6km away.Xiamen Island was considered to possess one of the world's great natural harbors in Yundang Bay, but Fujian's international trade was long restricted to Quanzhou or to Guangzhou in Guangdong. Due to the siltification of Quanzhou's harbor, the British insisted that Xiamen be opened to foreign trade in the treaty that ended the First Opium War in 1842. Under the Qing, both before and after the war, there was large-scale emigration of Chinese from southern Fujian spread Hokkien-speaking communities to Singapore, Malaysia's Penang, Indonesia's Riau Province and the Philippines. The overseas Chinese continue to support Xiamen's educational and cultural institutions. As part of China's Opening Up Policy under Deng Xiaoping, Xiamen became one of the original four special economic zones opened to foreign investment and trade in the early 1980s. Its former harbor was enclosed using land excavated during the city's expansion.