PORTLAND, Ore. – Thousands of people participated in Portland's World Naked Bike Ride on Saturday night.

This year's ride began at 9 p.m. at Fernhill Park in Northeast Portland. Riders began meeting at the park at 8 p.m.

The full route wasn't revealed beforehand but riders began heading south from Fernhill Park.

Photos: 2017 Portland World Naked Bike Ride

The event is part of an international clothing-optional series of bike rides that promotes positive body image, cyclist safety and denounces oil dependence.

Police urged riders at the bare minimum to wear a helmet and shoes to avoid any potential injuries. They also recommended bike lights, as well as plenty of water as the high temperatures reached the upper 90s on Saturday.

More than 8,700 people participated in last year's ride, which began at Mount Scott Park in Southeast Portland.