Nothing in this trip prepares one for the horror of Auschwitz-Birkenau.  When we arrived no one was allowed to go into the site without a guide-a matter of insuring that you got the whole, horrible story.  For those who need to learn more:  <https://www.history.com/topics/world-war-ii/auschwitz>.

Birkenau death camp was added to Auschwitz so that the killing could be done on an industrial scale.