Some 200 semi-nude bicycle riders snarled traffic in downtown Sao Paulo to protest car pollution and dangerous riding conditions in the city.
The demonstration drew the attention of motorists and passersby alike with no incident reported other than the arrest of one of the riders who had decided to take all his clothes off, city traffic officials said.
"Our nakedness shows how we feel as cyclists riding in traffic next to motorists well protected inside their vehicles," a demonstrator who preferred to remain anonymous told AFP on Saturday.
The naked pedal pushers were part of the World Naked Bike Ride, an organisation holding similar events in some 70 countries to protest "indecent exposure to cars."
"We face automobile traffic with our naked bodies as the best way of defending our dignity and exposing the unique dangers faced by cyclists and pedestrians as well as the negative consequences we all face due to dependence on oil, and other forms of non-renewable energy," the group said on its website.