Did you grow up believing something about your family that you came to find was untrue?

My grandmother proudly told people how she was related to US President, John Quincy Adams. We all repeated the story for years. Then when family members started doing actual research we found out there was nothing to it.

There was also a story about a baby being blown away in a tornado and being found safe later, but that turned out to be a conflation of stories from our family and others. It was exposed when no one could identify who the baby grew up to be.

Do you have stories that you grew up with that later succumbed to actual facts?