The pink triangle is one of San Francisco's most visible gay pride symbols and it appears that it was intentionally torched. A road flare was found nearby. The fire started just hours before San Francisco's 39th annual Pride Parade began.
Investigators are looking for clues and others want answers.
"Obviously we haven't made as much progress as we would like," said one man.
Many people that spoke with ABC7 Sunday said it was incidents like the one at Twin Peaks that give them reason to keep marching. The fire was not enough to dampen spirits at the parade.
"I think there's just too many people with hatred, but it's not going to dampen spirits," Elaine Hight of Oklahoma told ABC7.
The anniversary of the country's gay rights movement took center stage. This month marks the 40th anniversary of the 1969 Stonewall Riots, the defining moment in the gay rights movement.
"It was a lot riskier becuase just coming out in a march we could have lost our jobs. We could have been beaten up, all kinds of things like that," recalled Murry Edleman of New York.
This year's theme was pulled directly from the constitution, "In order to form a more perfect union." That statement about gay marriage that was not lost on the thousands who lined San Francisco's Market Street or the marchers in the parade.
"What do we want? Equal rights. When do we want it? Now," the crowds chanted.
Michael Beavers of Washington D.C. and his partner were married in Canada six years ago
"The politics has to be a part of it. Because, it takes politics to get the freedom that everyone should have to enjoy," he said.
Though California's Supreme Court upheld the state's ban on gay marriage, many who marched Sunday are among the 18,000 couples whose weddings remain valid.
"This is different because we have just had discrimination written into the law and upheld by the Supreme Court. We got something to march about this year. We've got to march," said Terry Minton of Concord.
"I'm fortunate that I'm still married to my wife. So, I'm pretty happy about that, but it's hard at the same time," said Vivian Moussa of San Jose.
The fire at Twin Peaks remained under investigation Sunday night by the San Francisco Fire Department. Police are assisting the investigation although it is not being considered a criminal investigation. It is also not being investigated as a hate crime.