A Tale Of Two Cities
I find the story of Kaspar Hauser, an anonymous teenager found wandering the streets of Nuremberg in the early 19th century, fascinating.
He appeared out of nowhere with no family, friends or anyone who could confirm his identity. He claimed to have been kept in almost total isolation for his whole life up until that point. His linguistic skills were severely limited, consistent with someone who had grown up with very little human contact.
Rumors began to circulate that he was actually a German prince who had been swapped at birth with a dead baby to prevent his succession to the throne by scheming relatives.
Rather than kill him, they locked him up in complete isolation and left him there to be forgotten until somehow he was freed or managed to escape. He attracted several wealthy sponsors over the course of his short life, but none were successful at solving the mystery of his origins.
He died under suspicious circumstances (stabbed by an unknown assailant) five years after being found. Of course, he may have just been a deranged fantasist or attention seeker. Who knows?
Story Credit: Reddit/HunchyTheHuncher