People lay down in a pedestrian zone as part of an art project in remembrance of 528 victims of the “Katzbach” Nazi concentration camp in Frankfurt

People lay down in a pedestrian zone as part of an art project in remembrance of the 528 victims of the "Katzbach" Nazi concentration camp, in Frankfurt, March 24, 2014. The inmates of the Katzbach concentration camp, a part of the former Adler industrial factory, were forced into a death march to the concentration camps of Buchenwald and Dachau on March 24th 1945. Some 528 victims of Katzbach are buried at Frankfurt's central cemetery. (Kai Pfaffenbach/Reuters)

People lay down in a pedestrian zone as part of an art project in remembrance of the 528 victims of the “Katzbach” Nazi concentration camp, in Frankfurt, March 24, 2014. The inmates of the Katzbach concentration camp, a part of the former Adler industrial factory, were forced into a death march to the concentration camps of Buchenwald and Dachau on March 24th 1945. Some 528 victims of Katzbach are buried at Frankfurt’s central cemetery. (Kai Pfaffenbach/Reuters)