Tens of thousands of revelers flooded the streets, sidewalks, bars and restaurants of West Hollywood early Saturday evening as the 27th Halloween Carnaval got underway.
Organizers said they were expecting as many as half a million people to attend the festival, famous for its elaborate costumes, uninhibited crowds and various degrees of undress. The city planned to livestream the event from Santa Monica Boulevard.
Its YouTube channel offered this warning: "Due to the nature of the event, viewer discretion is advised."
An hour after the official start time of 6 p.m., the area's sidewalks, bars and cafes were crammed.
There was also a heavy police presence. The Los Angeles County Sheriff's Department described the crowd as peaceful.
Musician Boy George was scheduled to give a rare performance. The event is also paying tribute to the 40th anniversary of the release of the cult classic "Rocky Horror Picture Show," the longest-running theatrical release in film history.
One of its stars, Tim Curry, was spending the evening as the city's honorary mayor.
Because of the scale of the gathering, several streets were scheduled to be closed throughout the weekend.
Major closures include Santa Monica Boulevard between North Doheny Drive and Croft Avenue from noon to 6 p.m. Saturday, and San Vicente Boulevard between Santa Monica Boulevard and Melrose Avenue to 6 p.m. Sunday.
West Hollywood will suspend parking restrictions from 11 a.m. Saturday to noon Sunday, and paid public parking will be available at lots throughout the city.
City officials encouraged participants to carpool or use public transportation. The city was operating its free, bright-yellow shuttle -- called the PickUp -- which will have a special route.
There will be about 1,000 "no parking" signs around the event zone for safety purposes and to control access.