What we do know about him are his actions, captured that day in stunning video footage.
The video shows the man blocking more than a dozen tanks that were rolling down Chang'an Avenue the day after hundreds of student protesters were gunned down by the Chinese military. The lead tank moves back and forth, trying to go around the man, but the man kept of blocking its path. The man then climbs up on the lead tank and appears to talk to one of the soldiers inside the tank.
The man is eventually led away by his arms by two men. It remains unclear if those men were police or security forces, or just bystanders who were concerned about the man.
In April 1998, Time magazine included the "Unknown Rebel" in a feature titled "Time 100: The Most Important People of the Century."
After all these years, the Tiananmen protests of 1989 still cause a swirl of emotions -- the fleeting hopes that the Chinese people might win human rights like voting or free speech which have eluded them, the crushing news that the uprising had been brutally suppressed, and finally the amazing courage of one man who was willing to risk the rest of his life to live as a free man for a few amazing moments of defiance. In this one image, Tank Man crystallized the eternal tension of modern civilization.
But what to think of the aftermath? In China, where citizens are not even able to post "6/4" on the Internet, the consequences have been grim:
When Zhang Xianling needs groceries, she passes three state security personnel stationed to watch her ninth floor apartment. Another four wait downstairs, along with a police car she must take to reach the market or go anywhere.
That's all because Zhang, 76, pursues justice for her son, Wang Nan, a student killed by an army bullet a quarter of a century ago when he was just 19.
Authorities prevent Zhang from meeting journalists or other Tiananmen Mothers, a group she co-founded in 1989 for relatives of those who died in the massacre. Ding Zilin, a spokesperson for the group, has been placed under house arrest, according to Amnesty International.
"At first we just did this for our kids, then we came to realize it's a problem of our country's political system," Zhang says.
The Chinese government decided to keep the Communist name but ditch the actual system -- the economic part. The grim repression of totalitarianism?....that, they kept. They gambled that the masses would accept a lack of human rights if they had a few more dollars to buy smartphones and the like. I'd love to report that such a cynical ploy failed, but it hasn't. The above USA Today article notes that only 15 percent of Chinese college students today recognize a photograph of Tank Man -- but is that really surprising? How many American college students in 2014 could recognize this?
Forgetting the rebels is just what societies do. But Tank Man marked a key moment in a year of global revolution that fell short in China but was still one giant leap for freedom elsewhere, most notably the collapse of the Berlin Wall a few months later. And his courage also inspired the generation that came after him -- to remind them that one man or woman can make a difference, even if the results aren't clear right away. In December 2010, a Tunisian grocer set himself on fire to protest that nation's lack of democracy. He didn't live to see what he had triggered -- the massive pro-democracy protests known as the Arab Spring.
The irony is that after a quarter century the world does not know who Beijing's Tank Man is, or whether he lived...or was killed or imprisoned. Yet maybe it's better that way, because now in 2014 Tank Man lives everywhere -- in Istanbul's Gezi Park and the slums of Rio and even in City Hall of Albuquerque, anywhere where the lost cause of true democracy is the only cause worth fighting for.