The entrance to the gas chamber at Auschwitz I, where Zyklon B was tested on Slavic prisoners of war. The building in the background is a hospital for German SS members. Auschwitz, Poland, date uncertain.

Auschwitz was the largest of the Nazi concentration and extermination camps, where over 1.1 million people, mostly Jews, were murdered during World War II. Located in occupied Poland, Auschwitz has become a symbol of the Holocaust's atrocities and is now a solemn memorial and museum.