The World Naked Bike Ride, or WNBR, a clothing-optional cycling event, drew hundreds of participants over the weekend in Mexico, where cyclists demanded respect on the road and called for expanded use of bicycles as an environmentally friendly mode of transportation.

WNBR participants took to the streets of Mexico City, Guadalajara and Morelia on Saturday, with some riders completely naked and others in their underwear.

Many riders arrived early, using the time to apply body paint and make signs.

"We came naked because that's how we are in traffic, fragile and defenseless because drivers constantly violate our rights on the road," cyclist Marco Delgado told Efe.

The cyclists also wanted to promote the benefits of bicycle use for the environment and health, and they sought to send a message about the need to cut the consumption of fossil fuels.

About 1,300 people participated in the event, according to Mexico City police, while organizers said only 624 riders registered.

The WNBR, which made its debut in 2003 in Vancouver, Canada, has been held in 70 cities in 20 countries, with cyclists hitting the road on the second Saturday of June to get their message across.