I have run five Chicago Marathons, and this is my big running event of the year. I've run other marathons, all lovely in their own ways, but nothing compares to Chicago in terms of the scenery, the crowd support, the big-city energy, and the field. You run with the best in the world, with lots of pacers for the mortals among us. Few hills, besides the final challenge of "Mount Roosevelt" at mile 26, traversing 29 neighborhoods throughout the city, including: dancing dragons in Chinatown, dancers in Boystown, Wrigleyville, United Center, the loop (a few times), Soxs park, Little Italy with Italian Ice, Pilsen blasting Mexican music and with little grandmas with buckets of oranges, the red brick buildings of IIT and Prairie Village, and 2 miles of Michigan Ave at the finish. Great organization, with 20 stations, 12,000 volunteers, and a beer at the finish. Highly recommended for the runner who wants big city excitement with a world-class field. The only downside was an ugly race t-shirt (worst in all my 5 times running Chitown), but there are plenty of sharp designs at the Expo and Fleet Feet stores.