A concentration camp was a prison where the many Jews, gypsies, homosexuals, disabled, Poles and Jehovah's Witnesses were sent by the Nazi regime. It is estimated that the Nazi party created and controlled 15,000 different camps which were found in several countries. These countries included Germany, France, Holland, Norway, Poland, Russia, Yugoslavia, Austria, Belgium, Czechoslovakia, Finland, Italy, Latvia, Lithuania and Estonia. Most of the camps were constructed near railways which was mainly how the prisoners arrived at the camps. Other times prisoners were forced to endure a long trek on foot to the camps.
Many of the infamous concentration camps resided in Poland. Chelmno, being one of the well-known camps, was known for its operation of three gas vans used for extermination. It used carbon monoxide and had the capacity to murder up to twelve thousand prisoners within a period of two days. Auschwitz was another infamous concentration camp which was widely-known for its size and number of casualties.
It was the largest camp ever built by the Nazi's and approximately one million Jews were killed while this camp was in operation. Belzec was the second concentration camp to come into operation, Dachau being the first. Belzec was famous for its gas chambers and the process in which they were used. Victims were brought on 20 freight train cars at a time and were immediately ordered to give up all possessions, including clothes they were wearing. They were then forced to run through a tunnel which led into gas chambers which were deceivingly labeled as "showers". The chamber doors were then sealed and carbon monoxide was released into the chamber, killing all those inside. This process was then repeated with the next 20 freight cars.
Nazi's and their allies ran several different kinds of concentration camps which had different categories.