CHICAGO -- Running may turn your cheeks red with the effort, but during Chicago's Color Run 12,000 participants ran and walked their way through Grant Park as they were doused with all shades of colors.
The Color Run was founded in 2011 and is in 35 countries. The founders say all the color is about having a good time, and not about how fast your mile time is (because everyone gets a unicorn medal at the end).
"Who doesn't like color? We have purple, pink, blue, green who doesn't like those amazing colors?" said runner Samuel Hazziez
The color mixture is made up of several ingredients, including some corn starch, food coloring and baking soda, and is meant to wash out of clothes easily.
WGN's Maggie Carlo reports from the "Happiest 5K on the Planet."