Candido Godol, a small town in Brazil, has long astonished the world with its very abnormally high level of birth rates for twins. The rate is nearly a thousand percent higher than the global average: "the 80 households in a one-square-mile area have reportedly some 38 pairs of twins. Blond, blue-eyed twins."
National Geographic Explorer is digging into this mystery and they have come up with a pretty out there, and horrifying, theory. They investigate claims that mad Nazi scientist Joseph Mengele, who escaped to Brazil, continued his research into using twins as a way to build a perfect Aryan master race. One historian thinks Mengele succeeded, and this town is the proof.
More information from NGE can be found here.