<Tr> <Th> Portuguese </Th> <Td> Região Administrativa Especial de Macau (for "Macau Special Administrative Region") pronounced (ʁɨʒiˈɐ̃w̃ ɐdminiʃtɾɐˈtivɐ (ɨ) ʃpɨsiˈaɫ dɨ mɐˈkaw) </Td> </Tr> <P> Macau (Chinese: 澳門, Cantonese: (ōu. mǔːn), / məˈkaʊ / (listen)), also spelled Macao and officially the Macao Special Administrative Region of the People's Republic of China, is an autonomous territory of China on the western side of the Pearl River estuary in East Asia . Macau is bordered by the city of Zhuhai in Mainland China to the north and the Pearl River Delta to the east and south . Hong Kong lies about 64 kilometres (40 mi) to its east across the Delta . With a population of 650,900 living in an area of 30.5 km (11.8 sq mi), it is the most densely populated region in the world . A former Portuguese colony, it was returned to Chinese sovereignty on 20 December 1999 . </P> <P> Macau was administered by the Portuguese Empire and its inheritor states from the mid-16th century until late 1999, when it constituted the last remaining European colony in Asia . Portuguese traders first settled in Macau in the 1550s . In 1557, Macau was leased to Portugal from Ming China as a trading port . The Portuguese Empire administered the city under Chinese authority and sovereignty until 1887, when Macau became a colony through a mutual agreement between the two countries . Sovereignty over Macau was transferred back to China on 20 December 1999 . The Joint Declaration on the Question of Macau and Macau Basic Law stipulate that Macau operate with a high degree of autonomy until at least 2049, fifty years after the transfer . </P> <P> Under the policy of "one country, two systems", the Central People's Government of the People's Republic of China is responsible for military defense and foreign affairs while Macau maintains its own legal system, public security force, monetary system, customs policy and immigration policy . Macau participates in international organizations and events that do not require members to possess national sovereignty . </P>

Macao was a colony of what european country