Explain the differences in what you were taught about slavery in Angola & here in the States.
For starters, in Angola the story always begins with the reason for the discovery of sub-saharan Africa in the first place; which is the fact that the Spanish (and the Portuguese) were looking for a route to India that did not include traveling the pirate riddled mediterranean sea (I'm talking late 1400's). So Diogo Cão was sent to circumvent Africa, of which the Europeans were only familiar with the North, and the man ended up chopping it up with the officials of the Bakongo Kingdom (North of Angola and South of Congo).

(basically it was the beginning of the fukkery breh).
Then we learn about the process of negotiations for slaves and introduction of religion (which the kings of Bakongo got completely enthralled by) and ultimately the invasion of the portuguese army in Bakongo soil. It's 12am so I'm not gonna get too deep into it.
It's kinda sad to hear an African-American painfully complain about how Africans just
gave their men and women away as slaves...and it's sickening when cacs say the same. But I always remind myself that most Americans aren't familiar with the story of the Kwata Kwata wars.
Eventually we have to learn about the transatlantic trade as it's the height of the slave trade in all of European history and it marks the point in time when the colonization began to bear it's most ripe fruits for the portuguese and cacs around the world in general.
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In the US the beginning of the European expansion is not really taught at all (maybe because Americans don't consider themselves european I guess). So all one really learns is about the process of slavery (how a slave farm was ran in America), the fact that slaves came from Africa (with Amistad as reference) and the civil war. There's more emphasis on the civil rights movement really, which makes sense as it's the movement that most African-Americans can relate to the most today.
Most of the history is left for autodidacts, the "Roots" book was introduced to me in America...and honestly I've never watched the movie, but I did read the whole book and the story of Kunta Kinte will forever reside in my memories.
Edit: Moreover I'd like to emphasize that as an African, there's much I gained from the emphasis on US education regarding the civil right's movement. That's because observing African-Americans dealings with the new forms of oppression is infinitely valuable for my understanding of the worldwide present history just as much as my knowledge of the past (gained in Africa).
The african-american battlefield is very different from my own back home, but both battlefields are intrinsically connected.
Meaning I can only gain from watching you all and understanding your struggles (which admittedly isn't hard at all once one learns of your history).