Chicago is actually one of the best cities to visit in the fall, so you won't find a shortage of things to do. There's local family-friendly novelties like apple-picking and pumpkin festivals, more traditional fare like tailgating at a Chicago Bears game, or something more urban like any of the great concerts that come to Riviera Theatre and the United Center.
I have always been one of those people to be oddly fascinated by the whole Jack the Ripper thing.. so i have always kind of wanted to take a tour of Whitechapel myslef.
