BEIJING — For many foreigners, he is Tiananmen Square's most recognizable figure, outshining even Chairman Mao Tse-tung -- whose body still lies in state at a far end of the vast public space.
Just after noon on June 5, 1989, the day after Chinese troops stormed the square to brutally crush a student political uprising here, a solitary protester engaged in a modern-day David versus Goliath showdown: Clutching nothing but two shopping bags, he stood his ground before a column of oncoming tanks on the adjacent Avenue of Eternal Peace.
Captured by newspaper photographs and cable news footage, the tense standoff lasted several minutes, a seeming eternity to onlookers waiting for the tanks to overrun the man, before he was hustled from the scene by onlookers.
On the 15th anniversary of the government crackdown in which hundreds, perhaps thousands, were killed, this lone dissenter's story remains the most enduring mystery of the violent confrontation.
No one knows whether he's dead or alive. Chinese activists and government officials say they aren't even sure of his name. After suddenly emerging to symbolize for the world the fierce power of the individual spirit in the face of martial rule, he vanished.
"For me, he represents the unknown soldier of the Chinese democratic revolution," said John Kamm, executive director of the Dui Hua Foundation, a San Francisco-based human rights group. "What's so strange is that his act of bravery was conducted in plain view of the world. But other than seeing his act, we know so very little about him."
The British tabloid Sunday Express shortly after the incident identified the man as a 19-year-old named Wang Weilin, the son of Beijing factory workers. But activists question the accuracy of a reporter they say did not visit China and relied on telephone calls to supposed friends of the man.
Others say the protester was a nongmin, a peasant from the countryside newly arrived in the city. But no one can say for sure. News footage and photographs showed him only from the back.
In 1999, on the 10th anniversary of the Tiananmen crackdown, Chinese leader Jiang Zemin was asked what had happened to the mystery man. He responded in English, "I think never killed." Jiang said government officials conducted their own search for the protester, checking morgues, prisons and computer registers, but could not find him.
But they could get no help from Chinese citizens themselves: No one in the country has ever seen the images. In fact, no ordinary Chinese beyond the protesters and soldiers involved even knows of the standoff. Even today, Chinese can't see the famous photograph, even on the Internet. Attempts to download the picture are blocked by the government.
On the eve of the anniversary this week, Tiananmen Square was crowded with thousands of tourists and locals milling under floodlights -- presumably watched by plainclothes policemen. Brigades of bicyclists passed on the crowded boulevards that surround the square, and a group of old women drew a curious crowd as they exercised to the beat of a drum.
Yet several people nearby said they had never heard of the tank man or his moment of fame.
"I've never seen him," one man said. "Was he Chinese?"
A couple dressed in Western clothing, holding hands as they walked along the sidewalk, said they were too young to recall the incident.
A nearby cab driver in his early 40s was old enough to remember the crackdown. But he said most people had just tried to forget what happened. When told of the exploits of the lone protester, he said, "He must have been a very brave man."
For the rest of the world, the image remains an icon of freedom. The protester has shown up in a Wim Wenders movie, and his image has been reproduced on posters and T-shirts. In 1998, Time magazine proclaimed him one of the 20th century's top 20 revolutionaries, whose "moment of self-transcendence [was seen] by more people than ever laid eyes on Winston Churchill, Albert Einstein and James Joyce combined."
Some believe the man endured months, or years, of political reeducation. Others say he was hunted down and executed.
Human rights activists say that 50 to 100 people were executed in the wake of the Tiananmen Square crackdown -- some for crimes as simple as burning a police motorcycle or, in one case, taking a photograph of the tanks in the square. In addition, 15,000 to 20,000 people were detained.
The activists say 99 still remain in prison for their actions during the protest. China has never acknowledged that civilians died in the bloodshed.
As for the lone protester, activists hope he has survived, but fear the worst.
"Either he's been killed already or he's still in some black hole in a Chinese prison," said Sharon Hom, executive director of the U.S.-based group Human Rights in China. "If he is alive and free, a man willing to stand in front of a tank would have come forward by now and not stay silent. This is not someone who is just going to disappear."