Well, let's start with this one.
"The Corwin Amendment." Never heard of it. Didn't know about it. Wouldn't have believed it if you had told me about it.
When I learned of it, and learned that it was real, it told me immediately that they were willing to sell all the slaves down the river.
That was a shock. It did not fit with what I had been told my entire life about the war to end slavery.
*Spoiler*: The Corwin Amendment was NEVER adopted.