Genealogy and migration
Historically there have been many migrations. During and after WW2 many Eastern European people moved to America. Before that Scots and particularly the Irish were renowned for setting up home in foreign lands.
There was also colonisation of countries and continents such as the USA and Australia. In later years, in the 1960s for example, there were even incentives on offer, such as cheap air tickets, to encourage people to leave the country of their birth and set up home elsewhere.
If you are interested in genealogy it’s quite likely that you may have to research the records of a country other than the one you now call home. Fortunately there are many online resources to help you.