Lake Shore Drive was closed for several hours Sunday morning to all traffic except the two wheeled kind.
About 20,000 cyclists took part in the annual “Bike the Drive”.
The event is an annual fundraiser for the non-profit Active Transportation Alliance.
The event lets cyclists make a noncompetitive round trip ride from Grant Park south to the Museum of Science and Industry then north to Lake Shore Drive’s northern turnaround point at Hollywood, according to an event website. Riders started at Columbus Street and Jackson Drive.