Will you teach me something new?

Anything you have learned recently that you found very interesting. I especially like medical discoveries, but am open to anything.

Recently I went to a local museum and learned things I never knew about slavery in America, I thought I kind of new everything there was to know on the topic. What I learned was when the plantation owners in the south were considering whether to purchase indentured servants from Europe, or slaves from Africa, most went with the Africans because their skin color was dark, and they would be easier to spot among southern citizens if they tried to escape. Also, historically slaves purposefully acted less intelligent, and seemingly unaware, to not intimidate slave owners, who might feel threatened. I found this information interesting and sickening. I realized I know a lot about the civil rights movement and segregation, but not slavery itself.