Birkenau, also known as Auschwitz II, was a Nazi concentration and extermination camp located in Poland during World War II. It was established in 1941 and became one of the largest sites of the Holocaust, where over a million people, primarily Jews, were murdered. The camp was part of the larger Auschwitz complex, which included several other facilities. Birkenau featured gas chambers and crematoria, where mass killings took place. Today, it serves as a memorial and museum, educating visitors about the atrocities committed there and honoring the victims of the Holocaust.