Two photographs of Dr. Josef Mengele (1911 - 1979), a German physician stationed at the Auschwitz-Birkenau concentration camp during World War II. The image on the left is from around 1956, and in the right-hand one, he is using the alias Ludwig Gregor. (Photo by Paul Popper/Popperfoto via Getty Images/Getty Images)
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Popperfoto Paul Popper/Popperfoto