After World War II, some countries in Europe decided that they wanted to remove German people from their land. This happened mainly because Germany had started the war and caused a lot of damage to these countries. The countries that did this believed that German people couldn't be trusted to live peacefully with others.
This process is called the expulsion of Germans. It meant that German people who lived in other countries were forced to leave their homes and move back to Germany. This was done by the governments of the countries they were living in, and it was not a choice for the German people.
Many German people were forced to leave their homes and belongings behind. They had to walk for days or weeks to get to Germany, with very little food, water, and other essential things to survive. Some died on the journey due to exhaustion, hunger, and illness.
In total, it is believed that about 12 million German people were expelled from different countries after World War II. This was a very difficult and traumatic experience for them, and it is still a sensitive topic for many people today.