Hong Kong ( (listen); Chinese: 香港, Hong Kong Cantonese: [hœ́ːŋ.kɔ̌ːŋ] (listen)), officially the Hong Kong Special Administrative Region of the People's Republic of China, is a special administrative region on the eastern side of the Pearl River estuary in southern China. With over 7.4 million people of various nationalities in a 1,104-square-kilometre (426 sq mi) territory, Hong Kong is the world's fourth-most densely populated region.
Hong Kong became a colony of the British Empire after Qing China ceded Hong Kong Island at the end of the First Opium War in 1842. The colony expanded to the Kowloon Peninsula in 1860 after the Second Opium War, and was further extended when Britain obtained a 99-year lease of the New Territories in 1898. The territory was transferred to China in 1997. As a special administrative region, Hong Kong maintains separate governing and economic systems from that of mainland China, and its people overwhelmingly identify as Hongkongers rather than Chinese.
Originally a sparsely populated area of farming and fishing villages, the territory has become one of the world's most significant financial centres and commercial ports. It was estimated to be the world's tenth-largest exporter and ninth-largest importer, and its legal tender (the Hong Kong dollar) is the world's 13th-most traded currency. Hong Kong hosts the largest concentration of ultra high-net-worth individuals of any city in the world. Although the city has one of the highest per capita incomes in the world, there is severe income inequality.
Hong Kong is classified as an alpha+ world city, indicating its influence throughout the world. Hong Kong is one of the most significant global financial centres, holding the highest Financial Development Index score and consistently ranking as the most competitive and freest economic area in the world in 2017. As the world's seventh-largest trading entity, its legal tender, the Hong Kong dollar, is the 13th-most traded currency. The city has the largest number of skyscrapers in the world, most surrounding Victoria Harbour. Hong Kong consistently ranks high on the Human Development Index, and has one of the highest life expectancies in the world. Over 90 per cent of its population uses public transportation. Air pollution from neighbouring industrial areas of mainland China has caused a high level of atmospheric particulates in the region.