Note: Testimony from Riis’s assistant and scholarly analysis indicate that the images that Riis presented were actually carefully staged manipulation. Prior to the flash powder night images were not possible. So "night" scenes had to be photographed during the daylight hours. The limits of photography at the time required subjects to stand still, even with flash powder. Some have questioned whether the people in his photos would have posed if they had known the captions of their photos would label them as standing in a “Den of Death,” or as living in a place where it was the “Survival of the Unfittest.”