For an estimated 45,000 runners, months of training will culminate with the 32nd running of the Bank of America Chicago Marathon, which will begin at 7:30am in Grant Park Sunday morning. The 26.2 mile race snakes through 29 of our city's neighborhoods, from the Loop north to Wrigleyville; looping back south and west through University Village, Little Italy, Chinatown and Bridgeport; before hitting the finish line back in Grant Park. The urban course creates an amazing tour of Chicago for the runners, while also being spectator friendly: over 1.5 million people are expected to stand on the sidelines cheering on friends, family or strangers. The marathon website offers spectator info. While the past two years have seen high temps create problems for runners, this year's race forecast calls for cool and rainy, with a high of about 50 degrees.

Friday Afternoon Diversion: Earth With Rings