From National Geographic Explorer:

"Joseph Mengele, the escaped Nazi war criminal and SS physician, known as the Angel of Death, spent years doing bizarre medical experiments on twins at Auschwitz working to determine if twins held the key to building a blond-haired, blue-eyed master race for Adolf Hitler. Now a historian says he has evidence that Mengele's attempts may not have ended at Auschwitz, and that his obsession to engineer an Aryan master race continued, and that succeeded while he was on the run in South America. Deep in the Brazilian outback in a tiny town among the 80 households in a one-square-mile area are reportedly some 38 pairs of twins. Blond, blue-eyed twins. Bizarre and inexplicable, could they be the product of Mengele's machinations? Now, with exclusive access, EXPLORER goes inside the investigation; From the secret agents who trailed him, to the scientists now uncovering the facts behind the fantastical phenomenon, no stone is left unturned."