The Nazi Party sets up the Oranienburg concentration camp on the site of an abandoned factory in Oranienburg, near Berlin. This is one of the first of the Nazi concentration camps in Germany and it's designed to hold political prisoners, mostly communists and socialists swept up by the SA and police at the time of the Nazi seizure of power.
Unlike later concentration camps, the Oranienburg camp is located right in the middle of a population center. Every day people can see inside the camp and prisoners are regularly marched through the town for provide labor somewhere.
The purpose of this camp is suppression of political dissent, not the extermination of enemies, so the Nazis have nothing to hide. On the contrary, it benefits them for people to see what happens to political opponents.
After the SA is eliminated and responsibility for concentration camps is taken over by SS, Oranienburg will be shut down and replaced by the Sachsenhausen concentration camp nearby.