The Nazis invaded Poland in 1939 and started a brutal occupation that lasted until 1945. During this time, the Nazis did many terrible things to the Polish people and their art, such as:
- Killing about six million Polish citizens, half of them Jews, in mass shootings, concentration camps, and ghettos.
- Forcing millions of Polish workers into slave labor in Germany and other Nazi-controlled areas.
- Destroying or stealing many cultural and historical monuments, buildings, and artworks, including the Royal Castle in Warsaw, the Wawel Castle in Krakow, and the paintings of Jan Matejko.
- Banning Polish language, education, literature, music, and religion, and trying to erase Polish identity and culture.
- Creating a puppet state called the General Government, which was ruled by Nazi officials and collaborators, and imposing harsh laws and taxes on the Polish population.
- Persecuting and oppressing anyone who resisted or opposed the Nazi regime, such as the Polish Underground State, the Home Army, and the Warsaw Uprising.