A group of nude bike riders took a cheeky approach to protesting this June in hopes of exposing more than just their bodies.

About 30 participants, mostly middle-aged men, bared it all to advocate bicycling as a form of transportation and to protest America’s dependence on foreign oil. The demonstration in D.C. was part of a worldwide initiative called World Naked Bike Ride, which has similar events in more than 70 cities and 20 countries, according to their Web site.

While none of the riders were completely naked, many were bearing enough skin to raise the eyebrows of tourists and passers-by. The riders wore flesh-colored sacks over their genitals or underwear, which ranged from American flag thongs to comparatively modest boxer shorts.

Roger Paul, 41, who organized the event, said he was pleased with this year’s turnout, which was up from only 18 participants last year.

“Our nudity represents the vulnerability of bikers on the road,” Paul said. “It’s also a visible way to draw attention to our cause.”

Another rider, Jeff Newton, described himself as a “home nudist” and said he was pleased to participate in a naked event.

“It’s a good cause,” Newton said. “We tried to get more women to participate, but I guess it just didn’t work out.”

With a chorus of “Show your hide, for your ride!” chants, the bikers set off down Vermont Ave., near the McPherson Square Metro stop, toward the District’s most famous landmarks. They headed past the White House and around the Capitol building, stopping twice to pose for photos.

Scott Dignan, a lieutenant with the Metropolitan Police Department, said he was present to protect the rights and well-being of the riders, rather than to curb their demonstration.

“We are not worried about them – we’re on hand to ensure they don’t receive any problems from the public,” Dignan said. “To show your buttocks in D.C. is completely legal.”