Researchers initially doubted the theory that Columbus and his crew brought syphilis back to Europe from the New World, because 50 European skeletons allegedly dating back to before Columbus's first voyage showed signs of the disease. But now biologist George Armelagos and his team have reexamined the skeletons, and found that most don't actually meet all the criteria for diagnosing the disease. And those that do are contaminated by carbon from seafood intake, which gets into bones and can make them look older than they really are. Result: there's currently no compelling evidence of syphilis in Europe before 1492, and Columbus might well be the culprit after all.
Since people don't always realise what a monster Columbus was, this seems like a good place to share a quote of his. He was addressing the native Americans.
"We shall take you and your wives and your children, and shall make slaves of them, and as such shall sell and dispose of them as their Highnesses may command; and we shall take away your goods, and shall do all the harm and damage that we can."