During World War II, from 1939 to 1945, Nazi Germany occupied Poland after invading the country. This occupation led to severe repression, including the persecution of the Jewish population and other groups deemed undesirable by the Nazis. Many Polish citizens were subjected to forced labor, and numerous towns and cities were destroyed. The occupation resulted in significant suffering and loss of life, with millions of Poles, including about three million Jewish Poles, killed during the Holocaust. The resistance movement within Poland, including groups like the Home Army, fought against the occupiers, contributing to the broader struggle against Nazi tyranny in Europe.