(CNN)From global leaders and pop stars to top athletes, the world paused to remember boxing legend Muhammad Ali, who dazzled with his lightning-fast jabs, his equally quick wit and unwavering principles.
#Greatest of All Time: How the world is mourning Muhammad Ali
"To the African-American community, he was a black man who faced overwhelming bigotry the way he faced every opponent in the ring: fearlessly," wrote NBA legend Kareem Abdul-Jabbar on Facebook.
Tributes came from his once-fiercest foes in the ring.
George Foreman, the two-time heavyweight champion who lost to Ali in the 1974 Rumble in the Jungle, mourned the man he called "the greatest piece."
Admirers shared his amazing skill in the ring -- how he appeared to bob and weave without effort, how his feet moved swiftly in a cartoonish blur.
Videos captured how precisely and quickly Ali moved, artfully dodging dozens of blows in a matter of seconds.
His speed and athleticism seemed so other worldly that even DC Comics had to show its appreciation of "a true superhero."
Fans remembered him beyond his athletic skills, including his stand against the Vietnam War draft -- even when such a position was unpopular. That steadfastness won him respect, boxing promoter Don King told CNN.
"People who didn't like him had to respect him," he said.
Soccer legend Pele posted an Instagram photo of himself, kissing Ali on the cheek.
"The sporting universe has just suffered a big loss," Pele wrote. "Muhammad Ali was my friend, my idol, my hero."
Former boxing world champion Manny Pacquiao tweeted, "We lost a giant today."
"He was one of my inspirations," Pacquiao told CNN. "His accomplishments, we will never forget."
Former astronaut Buzz Aldrin tweeted a photo of the day in 1988 that he rode with Ali in California's Rose Parade: "The world has lost The Greatest!"
Paul McCartney tweeted the image of Ali and the Beatles.
To President Barack Obama, Ali "shook up the world, and the world's better for it."
To African-Americans, he was a hero who refused to bow in the face of racism.
It was clear that the once-controversial boxer had been embraced into the mainstream.
Ali was a man who was proud of his religion and had changed his name to reflect his faith.
W. Kamau Bell, host of CNN's "United Shades of America," tweeted to "also remember that he was a Muslim."
Thomas Hauser, author of "Muhammad Ali: His Life and Times," said Ali's greatest legacy was the spirit of a man who "moved very deeply into hearts and souls not just in the United States but throughout the world. And all of us now carry some of Muhammad Ali in us."
He told CNN, "I think his greatest contribution to humanity is that there was an aura of pure goodwill and love about him. By his example he taught a lot of people how to love."