The Christiana Incident offers a snapshot of the U.S. when the country was sorting into states where slavery was upheld and states that had abolished it, and what racist tension looked like at border states in the mid-1850s.
Research:

SYMHC Classics: COINTELPRO 2
41:29

Behind the Scenes Minis: Whoopsy Whimsy
24:41

Great Lisbon Earthquake of 1755
39:02