With his monumental photographic project ‘People of the 20th Century’ Sander attempted to document social worlds in radical transformation in his native Germany. Taking a methodological approach, he classified more than 500 photographs into seven groups representing the social structures and employment divisions of the time. Shortly after World War II, Sander turned to the difficult subject of the persecution and elimination of certain social classes and groups by the National Socialists. The portfolio entitled ‘Political Prisoners’, from the group ‘The City’, depicts men incarcerated in Siegburg Prison, where Sander’s son Erich was held because of his left-wing political sympathies. Assigned the task of taking photographs for documentation purposes, Erich managed to smuggle some of the pictures to his parents, asking them to pass them on to the families and friends of those depicted. Sander later used copies of these photographs for his portfolio.