Auschwitz II and the remains of the gas chambers are also part of the museum .
The Polish government decided to restore Auschwitz I and turn it into a museum honoring the victims of Nazism ; Auschwitz II , where buildings ( many of which were prefabricated wood structures ) were prone to decay , was preserved but not restored . Today , the Auschwitz I museum site combines elements from several periods into a single complex : for example the gas chamber at Auschwitz I ( which had been converted into an air-raid shelter for the SS ) was restored and the fence was moved ( because of building work being done after the war but before the museum was established ) .