World War II evacuation and expulsion
Mass evacuation, forced displacement, expulsion, and deportation of millions of people took place across most countries involved in World War II. The Second World War caused the movement of the largest number of people in the shortest period of time in history. A number of these phenomena were categorised as violations of fundamental human values and norms by the Nuremberg tribunal after the war ended.
Source: Wikipedia — World War II evacuation and expulsion (CC BY-SA 4.0)