Photography by Lori M. Nichols

PHILADELPHIA — A small crowd of students began to gather on the steps of The University of the Arts' Dorrance Hamilton Hall shortly after 5 p.m. Saturday. While some people on the streets of Philadelphia may have been unaware of what was about to take place, these students were in the know: Philly Naked Bike Ride participants were about to pass by.

A few whistle blows from lead riders off in the distance quickly brought the students to their feet, and as the riders drew closer, shrieks, cheering and nervous laughter overpowered any other sounds typically heard on a Saturday evening in the city. And much to the students' surprise, one of the riders ran over to the group and posed for a selfie with them.

Hundreds of participants, mostly on bicycles — some chose other non-motorized modes of transportation such as skateboards or rollerblades — relished every moment as they rode through the City of Brotherly Love. Others hid their faces under scarves or costumes, knowing there would be plenty of people taking photos and videos of the "bare as you dare" event.

You do not have to be completely nude to participate; in fact, shoes are recommended for safety reasons. And many riders cover parts of their body with paint or stickers, or ride partially clothed.

Julaine Holihan, of Baltimore, brought her children, ages 3 and 6, with her for the ride. She wanted to normalize nudity for them, and desexualize it.

"Exposing kids to a positive atmosphere where they can feel positive and good about their bodies, about someone else's body, and know that people are different, they look different," Holihan said. "It's not a bad thing."

This year's 9.21-mile route — organizers change it each year — began at FDR Park and took the participants past famous Philly landmarks such as Pat's and Geno's, Rittenhouse Square, City Hall, and the National Constitution Center, ending at Eakins Oval. The ride took nearly two hours to complete.

Organizers said the purpose of the event is to promote the safety concerns of bicyclists and pedestrians as well as body positivity, while focusing on the world's dependence on oil.

"I like it because it's not really any political message," George Thuronyi, of Arlington, Virginia, said. "It's just people celebrating themselves."

Similar rides have taken across more than 70 cities the U.S. and 20 countries, according to WorldNakedBikeRide.org.

Scroll below for more photos of this year's Philly Naked Bike Ride.