CHICAGO (CBS) — One hundred years ago Saturday the 1919 race riots began in Chicago. Commemorative events were held throughout the city, including on the lakefront where the bloody conflict started.

One event was held by the DuSable Museum and the Chicago History Museum at 31st Street Beach.

Speakers talked about young Eugene Williams, a black teen on a homemade raft who drifted on the on the lake on July 27, 1919.

An informal line of segregation existed back then at the 29th Street Beach with whites on one side and African Americans on the other.

Williams drifted over.

A white man hit him with a rock, and the teen drowned.

The man who threw the stone was identified by other African Americans, and the police were called and told but refused to arrest the person.

The resulting riots claimed nearly 40 lives, most of them black. Hundreds were injured.

Some people wrote thoughts and hopes for the future on water soluble paper and released it into the lake.