The Nazis began their camp system soon after Hitler gained power, targeting political threats to the regime. Communist and socialist were among the first to be imprisoned. In approximately 1935, other people considered to be inferior to the Aryan race were also imprisoned. These people mainly consist of Jews.
The purposes of the camps obviously evolved over time. They went from imprisonment, to forced labor and outright murder.
With the Nazi party becoming more and more powerful, many people who resisted their domination were arrested and sent to such camps. People judged as being unacceptable to society were also sent.
As the war went on, more camps were built as the number of prisoners quickly grew. Within just three years, the amount of prisoners was four times as many as before the war.
When prisoners arrived at the camps from packed train cars, their personal belongings were taken away then they were immediately examined by doctors.
If they were incurably ill, they would be shot and killed. Prisoners with curable illnesses were sent to a camp hospital so that they would regain their strength. Every worker was important to the Nazis, the more workers, the more Germans could fight in the war.
Many people in work camps were literally worked to the point of death, the conditions were unbearable. Starvation or physical exhaustion were not uncommon.
Many prisoners were frightened of the Nazi guards and obeyed their orders. If they had not, guards would have had no hesitation in shooting them. Prisoners in work camps were often used as target practice for the guards.
The Germans often moved people from the work camps in Europe to extermination camps in Poland, where they were systematically killed. These camps were often equipped with gassing facilities for mass murder. The oblivious victims were told that they were going to shower and were then forced to remove every item of clothing. After being humiliated even more, they were sent into the gas chambers where they would die an unimaginable death.
It's been estimated that between 1933 and 1945, 1,600,000 people were sent to concentration work camps. Over a million of them died from a variety of causes, including starvation, random shooting, typhus and exhaustion. During the same time, around eighteen million were sent to extermination camps. Around five million were said to have been killed by systematic murder.