In the 50 years since a brick thrown at the Stonewall Inn in New York City started a riot and catapulted a movement, members of the LGBTQ community have marched down Halsted Street led by all sorts of exceptional grand marshals — a Puerto Rican boxing champ, TV stars, former NFL players.

But on Sunday afternoon, there was a grand marshal who made history: Chicago’s first openly gay mayor.

Last summer, Mayor Lori Lightfoot walked the annual Chicago Pride Parade as a long-shot candidate, holding hands with her wife, Amy Eshleman, who was wearing a “My Wife is Running for Mayor” shirt, as they marched down Halsted. This year, before Lightfoot tipped her hat to an endless wave of paradegoers — and a 90-degree day ended in a downpour that caused the parade’s historic anniversary to be cut short — she reflected on her political journey from marcher to mayor.

“It feels like I’ve come a long way,” she said.

“I think about 50 years past Stonewall, all the suffering and trauma that people have experienced,” said Lightfoot, “but there’s still a core spirit (and) people fighting to make sure that we have a place in our American history, that we have full rights of citizenship as anyone else.

“Our battles are not over, but today feels particularly sweet.”

For some who attended the parade, Lightfoot represented just how far the LGBTQ community has come in the past five decades.

Nikkia Stone, 37, of Oak Park, sat with some friends on a side street near Belmont Avenue. Stone, who identifies as a lesbian, said she has attended the parade for a decade. This year, she came to see the mayor.

“An openly gay mayor,” said Stone, with a smile. “It’s about being open and about being the person you want to be, that you choose to be.

“Being happy, being free, being yourself, enjoying it” — that’s what it’s all about, Stone said.

Lightfoot started Sunday at Lake View High School, where Gov. J.B. Pritzker signed an executive order aimed at protecting transgender students. She then headed to Fat Cat bar in Uptown for an Equality Illinois event. For at least a portion of the day, Lightfoot marched along the route in her rainbow checked slip-ons with police Superintendent Eddie Johnson.

Paradegoers prepared for the day in their own ways, taking time to remember why they take to the streets every June — or finding the perfect shade to complete a tulle tutu.

Before the parade began, Kevin Bogdan, 62, said it was his 18th year leading a float as “Thee Colonel” on “one of the happiest days of the year.”

“We had six girls from Nebraska come up one year,” said Bogdan, of Uptown. “I turned around, and all six girls were bawling their eyes out. They’d never seen so much love for the community and how the community embraces everybody. That’s what Pride is all about.”

Alex Sanchez, 25, prepared for the parade by going for a “Cinderella effect” — matching rainbow cape with flower crown.

Sanchez, who identifies as gay, has been coming to the annual parade since 2013. But, said Sanchez, “It seems more powerful this year.”

As the parade kicked off and flying beads and bubbles appeared in the sky above its 4-mile route, Haley Cutler, 26, of Highland Park, hung out with a group of friends in a Shell parking lot.

Cutler said she felt like she was in the middle of a historic moment.

“Just 50 years ago … there would be such a different reaction to this kind of display, and now people are so much more accepting,” Cutler said. “Obviously, we still have a long way to go, but I do think it’s beautiful there are so many people out here.”

Lightfoot, surrounded by a group waving colorful flags, walked by Cutler’s group.

“It’s incredible,” Cutler said. “It’s awesome that not only is she an openly gay woman, but she’s also African American. It shows to me a little bit of progress coming to Chicago.”

Below a white sky, some wearing glitter in every shade of the Pride flag and others wearing shirts with slogans like “Make America Gay Again” made their way through jammed crowds. Lightfoot stopped to receive a rainbow “Be the Light” banner.

One woman whom Lightfoot greeted put an arm around her and said, “I’m glad you’re the mayor.”

Lightfoot smiled for a moment. And then said, “Me too.”

A man hanging out of a second-floor window shouted: “Ms. Lightfoot! Want some beads?”

He tossed them down. She caught them. The crowd cheered.

But as the floats later in the lineup started to make their way south, the temperature dropped and the sun disappeared. Rainbow umbrellas went up, even as rainbow balloons topped with hot dogs continued down the parade route.

At Aldine Avenue and Clark Street, the rain started shortly after 2:20 p.m. Paradegoers took cover underneath Pride flags and shielded their faces with fans. Near the end of the parade route at Diversey Parkway and Broadway, the crowd started to clear out.

Attendees darted into the nearest coffee shop or took shelter under store awnings as it started to pour. Others gave in to the rain, walking slowly through puddles of green and blue glitter. A woman wearing a rainbow swimsuit and flip-flops covered her head with a small fan as she walked west on Diversey.

At 2:25 p.m. the parade was called due to a severe weather warning that forecasters said could affect more than 5 million people, according to Melissa Stratton, the director of the Office of Emergency Management and Communications. The cancellation, due to severe thunderstorms that brought the threat of strong winds, hail and intense rainfall, came about 30 minutes before the parade was slated to end, although a number of floats never got underway.

Chicago native Natasha Andrews, 71, stood undeterred near the end of the parade route, without an umbrella, wearing a black cap and Hawaiian shirt. Andrews said she has been to Detroit, Philadelphia and New York for other Pride parades.

“And it’s rained a number of times. As a matter of fact, these pants I have on, this was from New York,” said Andrews, pointing out an ink stain. “I was holding a sign and it faded on my pants. So I always wear these.”

Chicago police worked to open roads and break down barricades to make easier the mass exodus from the parade route. Firefighters and paramedics also were busy, tending to a number of people who were unresponsive amid the heat, and one person who suffered from cardiac arrest near the intersection of Roscoe and Halsted streets, said police spokesman Michael Carroll. About 1:15 p.m., in the 800 block of West Roscoe, a 56-year-old man collapsed on the sidewalk, according to police, and was taken to Advocate Illinois Masonic Hospital, where he was pronounced dead.

The bars along Halsted were lined with people hoping to take cover inside. Others made the best of the situation. At Halsted and Aldine, a crowd formed in a loading zone, loud music blaring, and launched an impromptu dance party.

Shannon Coppula, 22, who lives in the medical district, said she’s upset that Pride was canceled and even more upset about having to navigate through everyone leaving at once. But Coppula said she and her friends were planning to “tough it out” on packed transit lines to get away from the crowds.

On a Brown Line train headed north, the downpour’s effects were clear: a woman with a painted Pride flag melting down her cheek and another with mascara running down hers together resembled something like the artwork for Lady Gaga’s “Applause.”

But hours before the rain hit, while the sun made a rare appearance, Lightfoot talked about how the parade’s crowd reflects Chicago as “a beacon of hope.”

“This is a place where people can truly live their authentic lives,” Lightfoot said. “We’ve got work to do, particularly in making sure that our young people are not bullied in school, that they see themselves in the lessons of history that they’re learning.”

And, Lightfoot added, it’s important to stand up for the trans community and LGBTQ youths who are homeless and have been kicked out by their families.

When she reached the end of the parade, Lightfoot met with a scout leader who gave her a pin to represent inclusivity. The leader told Lightfoot that she wasn’t allowed to wear her uniform in a previous march, which led Lightfoot, visibly moved, to offer a hug.

At the end of the parade route, Lightfoot joined with her staff and supporters to pose for a group photo alongside her float.

On Sunday afternoon, standing next to her wife and daughter, Lightfoot swayed and sang along to a Diana Ross classic: “I’m Coming Out.”