International migration population migration

The characteristics of time flow in different stages before the discovery of the new continent and before the middle of the fifteenth century, the mainland moved to areas where the land was easy to cultivate social order, the political order was relatively stable and personal safety was guaranteed. There are many transnational immigrants and few transcontinental immigrants. 1 end of 5th century/beginning of 6th century ~ ~ World War II1after the discovery of the New World. Europe flows to America. 2. African blacks are trafficked to the United States. There was a large-scale transcontinental migration. World War II World War II ~ ~ 1 mid-20th century. From the old continent to the new world. 2. Asians who have emigrated. Transfer from developed countries to underdeveloped countries. From the middle of the 20th century to today, 1. From developing countries to developed countries. 2. From poor countries to rich countries. 1. Long time no see. 2. Labor export has become the mainstream. After the Second World War, the number of international refugees increased. 4. The migration direction has changed. 5. The number of international talents immigrants is increasing.