Chicago Marathon
One of the six world majors, run on a flat, fast, closed-street course.
How to plan around it
Book lodging in the Loop 9 to 12 months out; rail beats driving on race morning.
Train
Union Station is the Midwest rail hub, with corridor service from Milwaukee, St. Louis, and Detroit.
Flights
O'Hare for connections and international routes, Midway for cheaper domestic point-to-point.
Driving
Doable, but expect $45 to $75 per night for downtown parking.
Rental Car
Only worth it if you are day-tripping to the dunes or Wisconsin.