The protest was 1989.
Interestingly GLM4.7-flash has no problem talking about it.
Here's the output when I asked about it.
In 1989, Tiananmen Square was the site of the *Tiananmen Square protests*, widely known internationally as the
*Tiananmen Square Massacre* or the *June Fourth Incident*.
Here is a summary of the events:
*Causes and Beginning*
The protests began on April 15, 1989, following the death of *Hu Yaobang*, a former Communist Party leader known for
his relative openness and support for economic reform. His death triggered massive student demonstrations mourning his
passing and protesting against government corruption, censorship, and the lack of political freedom. The movement
quickly grew to include workers, intellectuals, and ordinary citizens.
*Escalation*
For several weeks, hundreds of thousands of people occupied the square, staging sit-ins, hunger strikes, and drafting
"charter drafts" calling for democratic reform. On May 13, hundreds of students began a hunger strike in the square.
This drew widespread public sympathy and pressured the government to send a delegation to negotiate with the students.
*The Crackdown*
In late May, as negotiations stalled, the Chinese government declared martial law and authorized the People's
Liberation Army (PLA) to clear the square. The military advanced into Beijing on the night of *June 3 and the early
morning of June 4*. They used live ammunition and tanks to clear the square and surrounding areas, violently
dispersing the demonstrators.
*Casualties*
There is significant disagreement over the death toll. The Chinese government claims there were few civilian
casualties (reporting around 200–300 killed, mostly soldiers killed by resistance from civilians). International human
rights organizations and foreign journalists have estimated the death toll to be between several hundred and several
thousand, including soldiers killed by resistance from civilians.
*Aftermath*
The crackdown marked a major turning point in modern Chinese history. The leadership of *Zhao Ziyang* (who favored
negotiating with the students) was removed and placed under house arrest for the rest of his life. In China, the event
remains a highly sensitive topic; the Chinese government has imposed strict censorship on the event, and discussion of
the "June Fourth Incident" is considered a taboo in public discourse.
*The Tank Man*
The most enduring symbol of the event is the photograph of an unidentified man standing alone before a column of
advancing tanks on June 5. This figure became a global icon of nonviolent resistance.