Hi there,

This is one question that comes up from time to time, so you might be interested in the FAQ on the topic.

The TL;DR of it is that the Holocaust was sort of an "open secret" in Nazi Germany in which most people tended to turn a blind eye, but anyone who was paying attention could plainly see that something very bad was going on. Many of the less sinister aspects of the Holocaust were not only carried out in plain sight, but were even championed publicly by the regime - things like the boycott on Jewish businesses, the creation of the first concentration camps (this is in contrast to the extermination camps), the passage of the Nuremberg Laws, the Reichskristallnacht (a.k.a. "The Night of the Broken Glass"), and the constant and ever increasing deportations "to the East" (which was a euphemism for extermination). The extent to which a random person was aware if the worst aspects (i.e. the mass shootings or the extermination camps and their gas chambers) is difficult to discern, mainly because there is a difference between what someone knows, what they should or could reasonably know, and what someone actually believes to be true.