Why Savannah?
Interesting that Savannah is the city that is presenting the greatest challenge/rebellion. Why is that the choice? Partly that it's about the right size: a small city, not major or high-profile, but historic. But what would cause THAT city to rebel the most?
One, the Southern rebellious streak. The large African-American population. The relative isolation from the seat of power, with a strong regional sense of pride and independence.
I like to think of the races in Savannah coming together to stick it to the Nazis.