Most notably, Mordechai Anielewicz (or a partisan named MA, with some similarities to the actual one) was one of the gazillion main characters throughout the series, so his death in 1943 is something I have to bear in mind when thinking of the actual history. Many more people in the Warsaw ghetto survived in the books, but a bunch of people in DC died at the hands of the invaders. It was complicated, as a world war plus an alien invasion might be...