The Nazis took things further, one step at the time. Jews had to start wearing a Star of David on their clothes and there were rumours that all Jews would have to leave the Netherlands. When Margot received a call-up to report for a so-called ‘labour camp’ in Nazi Germany on 5 July 1942, her parents were suspicious. They did not believe the call-up was about work and decided to go into hiding the next day in order to escape persecution.  
Use of the word "concentration" came from the idea of confining people in one place because they belong to a group that is considered undesirable in some way. The term itself originated in 1897 when the "reconcentration camps" were set up in Cuba by General Valeriano Weyler. In the past, the U.S. government had used concentration camps against Native Americans and the British had also used them during the Second Boer War. Between 1904 and 1908, the Schutztruppe of the Imperial German Army operated concentration camps in German South-West Africa (now Namibia) as part of its genocide of the Herero and Namaqua peoples. The Shark Island Concentration Camp in Lüderitz was the largest camp and the one with the harshest conditions.