Concentration camps started filling up in the year 1941, when the Germans began mass transports from the ghettoes in Poland to the camps. The people were transported all over to many different concentration camps some of which were known as, Chelmno Sobibor, Treblinka, Majdanek, and the largest one of them all which was Auschwitz-Birkenau. There was a specific process by which determined who would go first, and those people were the ones who were viewed as least valuable and least useful. The first mass gassings started at the camp known as Belzec, in the year 1942. After then 5 more mass killing centers were built at all the different camps which were being occupied in Poland. The transporting of the Jews to the concentration camps all over Europe took place for over a span of a couple years. The largest deportations to the camps took place during the early fall and early summer months of 1942. During this time more than 300,000 people were deported from the Warsaw ghetto. Since Auschwitz was the largest there were more than 2 million people alone murdered and killed there. The camps were used for Jewish and non-Jewish inmates to work hard labor sun up to sun down, and they were never feed and many came down with different diseases. Though only the Jews were killed by the process of gassing, the many other non-Jews ended up dying from complications such as starvation and disease. Hitler and the Germans used the concentration/death camps for many years, and well they tried to keep the operation of the camps a secret it was nearly impossible.