The world as we know it today was built through the displacement of women and men who about 70,000 years ago embarked on their journey from Africa to populate Asia and Europe, then Oceania and finally the Americas.
While most of these early movements were caused by climate change and the search for more food-rich lands, the constant mobility of women and men throughout history has led them not only to achieve many of the results sought, but also to increase their intellectual, cultural and social development, thanks to contacts with different environments and with different animals and human groups.
Since then, migrations have remained a constant throughout the millennia, even if sometimes they are perceived as a recent or even new phenomenon.
Over time, they have contributed to the development of technology, science and the arts through contacts and exchanges of knowledge, and have created cultural and human crossroads of incalculable richness. They have made it possible to establish links between communities of distant origins, but with common values. The European peoples, for example, would have had a different history if the Arab-Islamic peoples had not introduced Arab-Indian mathematics (numbers, algorithms...), naval technology and Chinese gunpowder, Arab medical and chemical discoveries, Arabic-Persian poetry, etc. into the European continent during their movements through various territories.
On the basis of its most evident motivations, different types of migration can be identified and distinguished: voluntary migrations, such as the first and second Greek colonization; forced migrations, such as deportations and the African slave trade; violent migrations, accompanied by genocide and extermination of local populations, as in the case of European penetration in America. Since the 19th and 20th centuries, economic crises have generated vast migratory flows from European countries to other countries on the continent, as well as to the Americas and Australia.
Today, migratory flows cross the planet from one end to the other because globalization phenomena have accelerated mobility. In richer countries, the main reasons for emigration are essentially economic: the improvement of professional conditions, the continuation of studies or better training courses for a better quality of life. In the countries of the South of the world, in addition to these pressures, there are other (more dramatic) reasons that put people's lives at risk, such as wars, persecutions, natural disasters, as well as the worsening of living conditions due to climate change (which affects the ability of farmers’ families in different areas of the South of the world to produce and obtain sufficient food).