Human migration is the movement by people from one place to another, particularly different countries, with the intention of settling temporarily or permanently in the new location. It typically involves movements over long distances and from one country or region to another. The number of people involved in every wave of immigration differs depending on the specific circumstances.
Historically, early human migration includes the peopling of the world, i.e. migration to world regions where there was previously no human habitation, during the Upper Paleolithic. Since the Neolithic, most migrations (except for the peopling of remote regions such as the Arctic or the Pacific), were predominantly warlike, consisting of conquest or Landnahme on the part of expanding populations.[citation needed] Colonialism involves expansion of sedentary populations into previously only sparsely settled territories or territories with no permanent settlements. In the modern period, human migration has primarily taken the form of migration within and between existing sovereign states, either controlled (legal immigration) or uncontrolled and in violation of immigration laws (illegal immigration).
Migration can be voluntary or involuntary. Involuntary migration includes forced displacement (in various forms such as deportation, the slave trade, flight (war refugees and ethnic cleansing), all of which could result in the creation of diasporas.