Nude Chicagoans — and other partially clothed people — stripped down for a cause and took to the streets Saturday evening for the 15th annual World Naked Bike Ride.

The yearly “bare-as-you-dare” event highlights body positivity and freedom from oil as its focal points — with organizers touting the bottom line of the day as “Less gas, more ass.”

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Starting at 8 p.m., riders in Chicago snaked from the Mag Mile to Boystown to Wicker Park for the clothing-optional ride.

Though bikes were the most popular mode of transport, any “person-powered wheels” were acceptable for the 14-mile ride around the city.

As many as 2,000 people have taken part in years past, organizers said.

The Chicago event is one of many naked bike rides across the globe, which started in 2004. Other participating cities have included Seattle, London and Vancouver.