Organisers have kicked off San Francisco's 40th annual gay pride weekend with a celebration in front of City Hall.
Thousands of people crowded into Civic Centre Plaza, where vendors sold barbecue and burritos, and DJs spun tunes on a large stage. Advocates for the lesbian, gay, bisexual and transgender community shared booths alongside corporate sponsors.
"It's part political, it's part a party," said Darryl Groom, 55, explaining the elements that brought him and his partner, Tobey Tam, 41, to San Francisco from Cape Coral, Florida.
The event continues with a parade and concerts by groups including The Backstreet Boys.
San Francisco's gay pride festivities have come a long way since the first parade in 1970, as has the GLBT movement, organisers and historians said.
The first pride parade had about 150 to 200 people, said Gerard Koskovich of the GLBT Historical Society.
"Barely anybody noticed," he said. "I've seen pictures of it."
The following year there was not even a march, he said, just a gathering in Golden Gate Park.
Now, the march attracts tens of thousands of people, and a growing number of those are not lesbian, gay, bisexual or transgender, Mr Koskovich said.
Events to mark the day were taking place across the globe, including Germany, Portugal, Mexico and Guatemala.