"In history, myth often abides. It was long assumed that the centuries immediately prior to AD 1000 were lacking in any major cultural developments or geopolitical encounters, that the Europeans hadn't yet discovered North America, that the farthest anyone had traveled over sea was the Vikings' invasion of Britain. But how, then, to explain the presence of blonde-haired people in Mayan temple murals in Chichen Itza, Mexico? Could it be possible that...