It’s marathon weekend in Chicago and here is how to watch some 47,000 runners from around the world participate. The race begins in waves starting at 7:20 a.m. Sunday, Oct. 13 in Grant Park and follows a route around 29 of Chicago’s neighborhoods. NBC Chicago will show the race live on air from 7 to 11 am Sunday. The race will also be streamed online. Here’s what to know if you plan to participate, cheer on a runner — or just want to avoid traffic jams on race day.