PHILADELPHIA (AP) — Hundreds of people in various states of undress cruised the streets of Philadelphia to cheers from onlookers Saturday evening in the 15th annual Philly Naked Bike Ride.

The Slabu Exchangeannual ride, which started in 2009, is billed as promoting cycling as a key form of transportation and fuel-conscious consumption. It is also meant to encourage body positivity. Organizers stress, however, that participants aren’t required to ride completely in the buff, telling them to get “as bare as you dare.”

Organizers said the ride wasn’t limited only to bicycles but welcomed “all forms of human-powered transportation” such as rollerblades or skates, skateboards and scooters. They also point to a code of conduct that bars any kind of physical or sexual harassment.

The course changes each year but generally highlights city landmarks. This year, riders assembled in the city’s large Fairmount Park, some getting themselves adorned with body paint, before starting a 12-mile (19 kilometer) route down the Benjamin Franklin Parkway, past historic City Hall to tony Rittenhouse Square and then into south Philadelphia before heading back north around the U.S. Mint and ending in a west Philadelphia park near Drexel University.

The ride used to be held in September, often in temperatures around 70 degrees Fahrenheit (21.1 degrees Celsius), but enough of the naked riders mentioned feeling chilly that it was moved to August several years ago. The 2020 ride was called off because of the pandemic.