Mexico City (AFP) - Five decades later, it is striking to recall how young they were.
Tommie Smith had just turned 24 and John Carlos 23 when the African American sprinters raised their gloved fists in a "Black Power" salute on the Olympic podium in Mexico City on October 16, 1968 in an act of defiant protest that reverberated around the world.
Fifty years on, as an old man whose prostate keeps him never too far from a bathroom, Carlos -- the more outspoken of the two -- is still as brash and bold as ever.
He regrets there has not been more progress on the problems he took a stand against that day: systemic racism in the United States and human rights abuses worldwide.
But he has not lost his optimism, he said on a recent visit to Mexico City.
Returning to the Olympic stadium, he reminisced about the moment he and Smith challenged oppression and changed their lives forever after winning bronze and gold, respectively, in the men's 200m.
"I went into the stadium, and I felt the same vibes that I felt in Mexico 50 years ago," Carlos said afterward at the National Autonomous University of Mexico.
"It felt like I was coming home."
His relationship with the events of that day was not always so easy.
The pair paid a heavy price for publicly shaming their country as its national anthem played.
Expelled from Mexico City and suspended from the Olympic team, they returned home as pariahs to a United States where the scars were still fresh from Martin Luther King Jr's assassination that spring and the riots that followed.
"When we went to Mexico City, there was like a bright sun that shined on the universe, and by the time we came home, it was like a big storm came," Carlos said.
He and Smith received death threats, lost their jobs and came under FBI surveillance.
Carlos recalled how one-time friends and teammates would walk away if anyone with a camera approached to take his picture.
It took him years, he said, to understand that "they're leaving you for fear. Fear of reprisals. Fear of what they've done to me, how they've ostracized me and Tommie Smith".
Both men's marriages fell apart as their lives slid into ruin. Carlos's wife committed suicide in 1977 -- "the greatest sadness in my life," he said.
"It was some desolate times."
Coffee with the FBI
Charming and funny, he kept his sense of humor through it all.
Slightly stooped but still spry, the gentle giant cracked up his audience with his stories, including one of how he spotted an FBI agent sitting in a car outside his house one day and invited him in for coffee.
The agent said he was close to retirement and could not risk breaking surveillance regulations.
"Well, I ask him if the rules state that I can't come out and have a cup of coffee with him," he said.
The agent finally agreed, and the pair chatted over coffee in his car.
A grinning Carlos drew laughs again when he objected to the Black Power label put on his protest. It was in fact part of the movement called the Olympic Project for Human Rights, he said.
"It was not a Black Power demonstration. If you want to see Black Power, that would be our black fannies running down the track," he said.
"We were concerned about human rights, humanity. And that crosses every sector of society."
After a stint playing American football was cut short by injury, Carlos finally got a job as a gardener in California.
There, he began picking up the pieces of his life as a changing nation slowly changed its mind about him and Smith.
By the 1980s, he was coaching high school athletics. By the turn of the century, statues were being erected in his and Smith's honor.
But his raw anger still flares when he talks about present-day racial strife in America.
From the Black Power of 1968 to the Black Lives Matter of today, from his raised fist to shunned NFL quarterback Colin Kaepernick's bent knee, little has changed in America's troubled race relations, he said.
"In terms of dealing with civil rights, a snail has moved farther in that 50 years than we have moved," he said.
He called Kaepernick "my hero," and shared some advice for the next generation of change-makers.
"When they come at you, rest assured, you're on the right track."