The term concentration camps has first been used in connection with the camps created by the Nazi regime. Concentration camps are places in which people are detained under the worst conditions, with no real basis for their arrest, at least when talking about the regulations of each democratic regime. In concentration camps, people were detained in conditions which hardly can be described as human, while their imprisonment was abusive.

The construction of concentration camps was established by law in Nazi Germany. The first concentration camps were created in 1933 and people were arrested and taken to such locations, where they have been retained until the end of the war, in 1945. Concentration camps were part of the Nazi regime and such camps were not only created in Germany, but also in the territories that entered under the occupation of Nazi Germany during the World War II. Adolf Hitler, the chancellor of Germany ordered the development of the first concentration camps just a few weeks after his election as the Führer of Nazi Germany. Concentration camps were build all over Germany and people began being arrested, most of the times with no real reasons or usually with invented charges. An impressive number of people were held prisoners in concentration camps. The concentration camps concept represented a new system of imprisoning people starting with 1934, under the supervision of SS leader, Heinrich Himmler. The concentration camps created in Germany were run by the SS, the elite guard of the Nazi party.

Starting with 1939, after the moment when Germany invaded Poland, new concentration camps were built on the territories occupied. Prisoners were forced to work until death in concentration camps. The Nazi have created numerous such locations, concentration camps being divided in different categories which included the hostage camps, in which hostages were held until being killed, labor camps, in which people were detained under inhumane conditions and the hardest treatment, being forced to work, POW camps, in which prisoners of war were retained and tortured, camps for rehabilitation, in which people were reeducated to become adherents of the Nazi regime and extermination camps, in which individuals were killed systematically, in time the Nazi developing new ways to exterminate prisoners more economically. Camps could also be created as a combination of the elements already mentioned, as most camps also had extermination systems.

At the end of World War II, most Nazi concentration camps were destroyed. However, some were made into memorials and are nowadays visited by tourists from all over the world. Visiting Europe and some of the most famous concentration camps is a great way to enter into contact with this part of the history and understand what prisoners have been through.