And there's no catch: it's free.
It will be 70 degrees by the time many runners finish the race.
She is the older sister of two-time Olympic gold medalist, Tirunesh Dibaba.
The marathon is timed when the city most needs the tourists dollars.
Finishers will receive a one-of-a-kind necklace.
The oppressive heat and humidity may have been partly to blame for the death of Chicago runner.