From the mid-20th century onward, emigration has been directed primarily to Western countries such as the United States, Australia, Canada, Brazil, The United Kingdom, New Zealand, Argentina and the nations of Western Europe; as well as to Peru, Panama, and to a lesser extent to Mexico. Many of these emigrants who entered Western countries were themselves overseas Chinese, particularly from the 1950s to the 1980s, a period during which the PRC placed severe restrictions on the movement of its citizens. In 1984, Britain agreed to transfer the sovereignty of Hong Kong to the PRC; this triggered another wave of migration to the United Kingdom (mainly England), Australia, Canada, US, South America, Europe and other parts of the world. The Tiananmen Square protests of 1989 further accelerated the migration. The wave calmed after Hong Kong's transfer of sovereignty in 1997. In addition, many citizens of Hong Kong hold citizenships or have current visas in other countries so if the need arises, they can leave Hong Kong at short notice. In fact, after the Tiananmen Square incident, the lines for immigration visas increased at every consulate in Hong Kong.