I, of course, knew that Auschwitz was a death camp but knowing something and then seeing it up close are two different things. The original Auschwitz invokes cognitive dissonance because while the markers of it being a horrible concentration camp are there, its prior existence as a Polish army barrack is also evident. The exterior of the buildings doesn't look like a concentration camp because that's not what they were built to be. The guard towers and the electrified barbed wire are markers of the horror of the place. The exhibits in the museum drive home horror. Piles of suitcases, shoes, and eyeglasses from those murdered by the Nazis are evidence of the evil.
Auschwitz II - Birkenau is horror on an almost incomprehensible scale. It's a factory of death that the Nazis purpose-built to scale up their evil murder machine. Over a million people were murdered at the Auschwitz camps. Almost 90% of the murdered were Jews. Many were murdered on arrival. Those selected to become slave laborers did not survive the inhumane conditions for long. Birkenau's size drives home the immensity of the Nazi's evil.
I found Auschwitz to be a difficult place to visit because the visitor is confronted with an evil where both the depth and scale of it is unmatched by almost any place on earth. The place is an important reminder of where hate leads and should galvinize all of us to give Neo-Nazis and related movements no quarter.