(CBS) — The warmest day of the year so far brings hundreds of mischievous teens to Michigan Avenue. Police are calling it ‘mob action’. CBS 2 is learning about multiple incidents in at least four different locations along the Magnificent Mile and in the Gold Coast, yielding a slew of arrests. Things got pretty bad, very quickly with many innocent shoppers and tourists caught in the middle of a very chaotic situation. Hundreds of teens littered Michigan Avenue and State Street near Chicago. Things started to go bad around 6:00 p.m. Saturday, with teens purposely bumping into people, and causing fights among themselves. Fifteen juveniles and two adults were arrested and charged with Reckless Conduct— a misdemeanor. Community activist, Andrew Holmes witnessed some of the problems, while shopping with his family.