According to the Oxford Companion to World War II, over a million people (1.2-1.5 million) were murdered at Auschwitz. Although the Nazis strove to destroy a great deal of the evidence of their crimes, much remains. On one lane in the original camp (Auschwitz I) stand gallows. Not far way is a wall where thousands of prisoners (largely Poles, Russians, and Hungarians) were shot. The infamous gas chambers were mostly at a nearby camp (Auschwitz II, also known as Birkenau), and the SS blew those up; however, an earlier gas chamber with a crematorium still stands in Auschwitz I.

Auschwitz I began as a slave labor camp, and a gate still shows the SS motto found in such camps: Arbeit Macht Frei (work makes freedom.) Auschwitz II, in contrast, was set up as an extermination camp comparable to those that were part of Operation Reinhard. Although Jews from Poland and other nations of Eastern Europe were by far the most numerous victims, many other people also went to their deaths at Auschwitz. The Gypsies were a prime target of Nazi hatred, and one building focuses on their plight, listing thousands of names of people known to have died in the camp. Still other captives suffered the cruelties of Nazi science. One building is remembered as the site of gruesome experiments with women prisoners. The government of Poland has maintained Auschwitz as a museum. Few if any visitors leave untroubled.