Doors into the homicidal gas chamber
The first two photographs below show the door leading from the undressing room into the gas chamber disguised as a shower room. A sign on the wall above the door says "Brausebad" which is the German word for shower room. American soldiers who toured the crematorium in the first few days after liberation described the room where this door is located as being furnished with a table holding a vase of fresh flowers, along with soap and clean towels. Notice the window in the undressing room and the oak floor.
In the first photograph, you can see that the door is the kind that was used for protection in air raid shelters, as well as for homicidal gas chambers in the Nazi camps. The second photogrph shows the same door taken from the other side. In the US Holocaust Memorial Museum in Washington, DC there is a casting of a door to a homicidal gas chamber in the Majdanek death camp in Poland which is exactly like this door, except that the Dachau gas chamber door has no peephole. The USHMM shows a photograph of the casting in the musuem on this page at their web site: http://www.ushmm.org/misc-bin/add_goback/outreach/892-1.htm