The international 5k is held as a shakeout run for the Chicago marathon. It is amazing in that many family members and friends of marathoners will join in the fun though they will not be running the marathon. There is such a feeling of family and community on the course. Because people come from around the world to run the marathon, the 5k is just as diverse. You start and finish feeling a sense of accomplishment because of the great sense of unity on the course. Spectators are amazing. Highly recommend this race for all levels as it is not a competition for the most part. It is about coming together as one big sole-family.