ELI5: Explain Like I'm 5

Terra nullius

Terra nullius means 'land belonging to no-one.' It’s a term used to describe land that is seen as empty and unclaimed by anyone. This phrase is sometimes used to explain why some countries have taken or claimed land that already has people living on it. This means that the people living there don't have any rights to the land, and the country taking it doesn't have to pay them anything or ask them if it’s okay.