Just saw the movie and learned several new things about Harriet Tubman. In addition, I should not have been so surprised, but was struck by how the underground railroad closely mirrored a clandestine intelligence operation, in this case involving a network of support assets who helped exfiltrate slaves from a hostile territory, led by a particularly daring, courageous and skillful "defector" (Tubman) who knew how to outwit the enemy on their own turf (apparently aided by divine intercession, a la Joan of Arc).