The thing about a party that has been going on for 30-plus years is that a lot of people know about it.

And the fact that Toronto was hosting WorldPride this time around, for the first time ever, means that Sunday’s annual parade was simply a massive event.

Those who wanted a front-row seat to the parade had to show up early.

Toronto police Const. Laurie McCann captured this image of the WorldPride parade and the massive surrounding crowd from the rooftop of the Marriott Hotel in downtown Toronto. (Tweeted by @thecoffeecop)

Kathy Czarnecki-Smith and Tina Czarnecki-Smith staked out their spot on the sidewalk at 9 a.m.

The married couple from Erie, Pennsylvania, heard that the crowds would be huge, so they had their breakfast and began camping out on the parade route.

"To come from such a conservative city where we live in Erie, to here where it is such an amazing, amazing display of people and humanity," Kathy Czarnecki-Smith told CBC News.

"We love to see everything."

More than 12,000 people had registered to march in the downtown event, which got rolling at about 1 p.m. Some walked, some roller-skated, while others rode on floats or motorcycles.

The temperature was well into the mid-20s before the parade started. And with the humidity, it felt like the mid-30s.

The parade began at Church and Bloor streets, with participants heading over to Yonge Street and then turning south, winding their way to Dundas Street in Toronto's downtown core.

City sidewalks were jammed with spectators. Others watched from rooftops or from buildings lining the parade route.

John Carr, who also hails from Erie, said it was worth the drive to come to WorldPride and see the parade.

"It’s three and a half hours away and I absolutely love Toronto, so, it's nice coming to an area where we’re accepted for who we are," he said.

Among the crowd were many people who were Pride parade veterans — those who come to the event year-in and year-out.

Debanjan Sen came to Toronto from India a few years ago. He told CBC News that he's come to Pride every year since.

The WorldPride parade rolled on for hours on Sunday afternoon, as thousands of participants made their way from Bloor Street down to Dundas Street in downtown Toronto. (Jasmin Seputis/CBC)

Sen said he and his partner feel more welcome in this city, more able to live the life they want to live.

"We don't need to compartmentalize our lives here as we would do there," he said.

There were floats, many colourful costumes and many, many variations on the rainbow flag that were shown off throughout the day.

Even a robot was rocking a rainbow — or at least a person dressed as a character from Transformers that had been renamed Optimus Pride.

A number of Toronto councillors attended Sunday's parade, as did Premier Kathleen Wynne, Ontario NDP Leader Andrea Horwath and a number of other MPPs. Federal NDP Leader Tom Mulcair and Liberal Leader Justin Trudeau were also at the parade.