Fort Pillow, perhaps most horrific massacre of the Civil War.
Community's Pillows and Blankets episode, definitely the most hilarious parody of KenBurn's Civil War
When Confederate troops led by Nathan Bedford Forrest overran Fort Pillow in Tennessee, they slaughtered the black Union troops
rather than taking them prisoner. This remains one of the most controversial episodes of the war.
On the other hand, the Community episode parodying Ken Burns' documentary
was absolutely hilarious (and free of racist vitriol). I'm pretty sure the writers had no idea there was a Fort Pillow in the actual war ... probably for the best.