It was known as the "Red Summer."
This is the third year organizers have hosted an event to remember those race riots, this time 102 years later. The goal is to educate the public about that violence to root out racism.
Those Chicago race riots are known as the worst incidents of racial violence in the city's history.
In the summer of 1919, an African American teenager crossed over to a segregated whites-only area of a South Side beach.
SEE MORE: Chicago's Race Riot of 1919 left 38 dead, 2 years before Tulsa Massacre
White people threw rocks at that teen, and he drowned, sparking the week-long riots, which left 38 people dead.
Organizers said Saturday's 5.5-mile bike ride would explore this history and also talk about Chicago's residential segregation and Black resilience.
"Denying, not remembering, ignoring the past has not resulted in the equitable society that we claim to believe in," said Peter Cole, a professor of history at Western Illinois University and founder of the Chicago Race Riot of 1919 Commemoration Project. "So if you want to make the same mistakes and have the same results, we can do that. For 101 years we've been doing it. If you actually want to make the city and the country a place where we actually all are equal and all have justice, we have to do something different."
Dozens of bicyclists rode through Chicago's South Side Saturday morning.
"It was just sad," participant Mary Garnett said. "And then it spilled over into the neighborhoods."
"A Black child was killed for swimming in the lake. He simply crossed an invisible line that he didn't know existed that segregated Lake Michigan," he said. "After 1919, the city elite basically doubled down on racism and segregation."
Alice Li, a participant, said she's new to the city.
"I think it's important to learn its history, especially in context of what happened and what's going on currently in our environment, and also I like biking so it was perfect," she said.
Darius Lawrence, the ride marshal, said he was still learning about the history and what it meant to his culture and the city as a whole.
"To know where we come from, to know that we still have some change to happen, we need to be a part of that as a group, collectively, to make that change happen," he said.
A headstone was also unveiled Saturday in Alsip for Eugene Williams, the teen whose death sparked the 1919 race riots.
He was buried in an unmarked grave for more than a century.
Now there's a grave marker in his name at Lincoln Cemetery.