Waves of mass migrations from Hong Kong villagers exercised their right of abode in the United Kingdom and left for Europe. In 1967, a series of large-scale riots erupted in Hong Kong, causing social instability. These events led some of the richer Hong Kong residents to move abroad. Emigration took place to countries in Southeast Asia, South Africa or South American countries. This wave did not come to a rest until the mid-1970s. On the 19th of December 1984, the People's Republic of China and the United Kingdom signed the "Sino-British Joint Declaration", validated the 1997 transfer of sovereignty over Hong Kong to China. The declaration prompted
British Hong Kong the Convention of Chuenpi during the First Opium War. On 20 January, Elliot announced "the conclusion of preliminary arrangements", which included the cession of Hong Kong Island and its harbour to the British Crown. Elliot chose Hong Kong instead of Chusan because he believed a settlement further east would cause an "indefinite protraction of hostilities", whereas Hong Kong's harbour was a valuable base for the British trading community in Canton. British rule began with the occupation of the island on 26 January. Commodore Gordon Bremer, commander-in-chief of British forces in China, took formal possession of the island at Possession Point,