And a big old van, looking like something out of the Mad Max movies, led the crowd with booming music.
As we walked, though, I was looking for Zach Wahls, who had emailed me to say he was "super tall, can't miss me." I'd replied, "super short, can miss me." I finally spotted him, wearing a backward ball cap, white T-shirt and jeans and walking with a woman who looked even shorter than me.
Zach is the guy whose 2011 speech to an Iowa legislative committee launched his incarnation as a nationally recognized LGBT activist. He is the author of My Two Moms: Lessons of Love, Strength, and What Makes a Family.
After the parade, Zach and one of his moms, Jackie Reger, sat with me at a picnic table. What, I asked, had compelled him to confront Iowa lawmakers about a proposed state constitutional amendment to ban same-sex marriage in a place where such unions already existed?
We started with a little history. Zach was born to Terry Wahls, a physician, in 1991. Three years later, his sister was born. In 1996, Jackie and Terry had a commitment ceremony and later were married.
Zach said he'd grown up being compared "to a child-abuse victim. I was called deficient, broken, flawed. My family was not a real family. I still get it today."
Growing up in the '90s, he said, "I worried the government would take me away."
But he also had parents who instilled a love of books, learning and compassion. (Jackie is a physician's assistant.) He debated in high school and pursued a degree in sustainability studies at the University of Iowa until his fame took him to TV, radio and personal appearances to campaign for LGBT rights.
"The speech itself, and everything that happened after, I think it was a very powerful reminder of the strength that words still have," he said. "Sometimes I think we forget that oration has always been a part of this country's history. And to have been a small part of that history is an incredible honor."
Zach believes that the struggle is the civil rights movement of our time.
"I firmly believe we are on the right side of history," he said. "And after saying you have the moral high ground, you have to walk that road. Darkness cannot erase darkness, just as hate has no hope of ever erasing hate."
Zach has been featured on CNN and MSNBC talk shows. Just last week, Anderson Cooper had him on his show. He hasn't made Rachel Maddow's show, but they've met. Zach thinks Maddow has the intellectual firepower that's well-suited for her style of commentary. He just finished her book, Drift: The Unmooring of American Military Power.
He's also, as he put it, "actually infatuated" with her.
The last year and a half have been a whirlwind for Zach, and at 21 he knows it won't last forever. "If this is a job, I'm trying to put myself out of work," he said.
Still, the experience might propel him into environmental activism, what he calls the next big rights movement. At present, he has no political ambitions.
But at 21, he has brought a measure of experience and clarity to the national debate on same-sex marriage and its rights and responsibilities.
And while there were the wild dressers and dancers, rally cries and T-shirts labeled "Utah Gay Fathers," the paradegoers who gathered in the Old City Park did what families do. They browsed the booths, listened to live music and gathered on blankets and camp chairs.
To me, it was impossible to imagine them as something other than people who love each other like Zach, his sister, Zebby, and their moms.
Peg McEntee is a news columnist. Reach her email@example.com, facebook.com/pegmcentee and Twitter, @pegmcentee.