The tanks that rolled towards Tiananmen Square 25 years ago not only crushed China's hopes for democracy; the impact of those events still resonates today.
The government's military crackdown on protesters in June 1989 - which killed hundreds, and perhaps more than 2,000 demonstrators - fuelled further corruption, inequality, and sowed the seeds of discontent and social instability for years, historians and analysts say.
Since Tiananmen, Beijing has tightened control on debate and increased its suppression of dissent because officials believe they need to maintain one-party rule at all cost, the experts say. Politically, the crackdown closed off the possibility of political liberation for the foreseeable future, they say.
Watch: Key facilitator of Operation Yellow Bird reveals how Chinese activists entered Hong Kong after June 4 crackdown
The crackdown "trapped the regime itself in an authoritarian model from which it is difficult to extricate itself and trapped the public in a state of political disenfranchisement and apathy," says Andrew Nathan, a political science professor at Columbia University. The subsequent generations of leaders have shown no signs that they wish to liberalise the nation's politics, he says.
When soldiers opened fire on the Beijing protesters on the night of June 3, 1989, it was "an important turning point" for China, says Perry Link, a sinologist at the University of California at Riverside. He says the extreme force of tanks and machine guns is seared into the memory of ordinary Chinese, that they must not step outside the authorities' boundaries.
"The fundamental goal was to preserve and extend the rule of the Communist Party of China," he said.
After the crackdown, the party purged reformist leaders and officials, and stalled fledgling political changes. Party chief Zhao Ziyang was removed for sympathising with students and placed under house arrest for nearly 16 years until his death in 2005. His political reform plans - legislation for press freedom, the separation of party and government functions, and increased political participation from civil society - were abandoned.
Dr Wang Juntao, who was in 1989 deputy editor of the liberal Economics Weekly in Beijing, says the crackdown has a "very bad consequence" of bringing China's democratisation process to a halt and "killing off China's reform … making it politically even more dictatorial".
Before Tiananmen, people in all strata of society yearned economic and political reforms to curb corruption and grant citizens more say in how the country was run. Deng Xiaoping, then the chairman of the central military commission, worked throughout that time on economic development.
Without checks on officials' power, an elite class grew stronger, enjoying advantages that ordinary citizens never had.
"Deng wanted to nip opposition in the bud. He wanted political stability to carry out reform more smoothly, but forgot that authoritarian rule bred corruption," says Wang, who was jailed for "inciting, organising and masterminding a counter-revolutionary rebellion" in the Tiananmen movement and later went into exile in the US.
"After that, there was economic development, but that gave rise to crony capitalism, so Deng was mistaken," he says.
Journalist and historian Yang Jisheng says many people believed the party would address the country's problems with political reforms, but that changed after the crackdown. Student demonstrators, who had demanded dialogue with the government, denounced corruption among officials.
"What kind of a 'people's government' is that? How can this be?" he asks, referring to the public's disbelief at the crackdown.
An elderly former official, speaking anonymously out of fear of reprisal, says many people learned after Tiananmen that "if you rely on Deng [Xiaoping], there is no hope for democracy and freedom. Only dictatorship will continue".
After the protest was suppressed, political reform became taboo. Deng, however, insisted that market reforms continue. Those changes fuelled stellar economic numbers and prosperity for many as the economy grew to be the world's second largest.
But without checks on official power, it spawned unbridled corruption, one of the widest rich-poor gaps in the world and social discontent, analysts say.
"Corruption … is made much worse in an authoritarian system where there are no independent checks on power - free press, independent courts, independent NGOs," says Link.
Still, market reforms were carried out only partially. Control of lucrative businesses remains in the hands of the state and a powerful elite class of officials and their associates who can trade their political power for money and influence. This has exacerbated social inequality and spread discontent, analysts say.
The crackdown also shifted the nation away from a hopeful idealism to materialism and patriotism, Link says.
Days after the crackdown, Deng told the army the party had erred in failing to instil "thought and political education" among ordinary people, including principles such as "dictatorship of the proletariat" and the leadership of the Communist Party.
Link says that Deng's long-term project of stimulating nationalism and educating the masses in the formula "party equals country" was effective.
"The groping for moral values today is a pretty direct result of Deng's massacre followed by his 'education' of the people in nationalism and money-making," he says. "Without the massacre, that turn could never have been so sharp."
Chinese leaders continue to view the Tiananmen protest as taboo. For the past 25 years, the party has scrubbed mentions of the events from histories and punished those who have tried to commemorate the protests. Each year, police place scores of people under house arrest or in arbitrary detention in hostels ahead of June 4. Officials this year detained a dozen people for criminal investigations.
Days after 15 people took part in a private gathering on May 3 commemorating Tiananmen, police placed five in criminal detention, including scholars Xu Youyu and Hao Jian, lawyer Pu Zhiqiang, house church leader Hu Shigen and online writer Liu Di. They were detained on the charge of picking quarrels and provoking trouble.
This year, ahead of the anniversary, more than 30 activists, lawyers and scholars have been detained, arrested or placed under house arrest, according to Amnesty International.
Professor Jean Philippe Beja, a senior researcher at the French Centre on Contemporary China in Hong Kong, says authorities are particularly wary of organised activities and political discussions, as they fear social conflicts will turn into political demands.
"It's still a question of, if you allow dissenting voices to express themselves, you threaten the monopoly of the political realm," he says. "The bottom line is, no organisation, and you don't challenge us directly."
Analysts say leaders avoid touching on the wounds of June 4 for fear of opening a floodgate of political demands. Seeing themselves as "political heirs" of the Communist regime, they also fear that political liberation and granting basic rights to citizens would lead to the collapse of the regime.
"The bottom line is to maintain the grip on power. To open up the question of Tiananmen massacre would threaten this grip, because once the questioning starts, nobody knows where it will end," Nathan says.
The preamble of the constitution stresses the "dictatorship of the proletariat" and "the Communist Party's leadership", Beja notes. "So, monopoly [of power] is its basic nature - it's one party and that's it," Beja says.
But if today's leaders addressed the history, it could bolster their political power, Yang argues, pointing out that when the party admitted in 1981 that Mao Zedong had made a mistake with the Cultural Revolution, leaders were able to move onto a new era of reform. "To walk out of Deng's shadow, there must first be an objective assessment of Deng," he says.
Another elderly veteran party member and ex-official, who declined to be named, says that the authorities must admit their guilt and release historical facts about the crackdown as a first step towards reconciliation.
"If there is no forgiveness, there will be no future," he says.
1989: The Countdown
April 15: Former Communist Party chief Hu Yaobang dies of a heart attack.
April 17: Student protesters gather at Tiananmen Square, commemorating Hu and calling for democracy and reforms.
April 22: Top leaders attend Hu's funeral in the Great Hall of the People on the west side of Tiananmen Square, with tens of thousands of students and workers outside.
April 26: Chinese official media break their silence on the protests. The Communist Party's mouthpiece, People's Daily, runs a front-page editorial, defining the student movement as an anti-party revolt that should be resolutely opposed.
April 27: About 50,000 students defy government warnings and break through police lines on way to Tiananmen Square, marching against government corruption and demanding the government rescind the People's Daily editorial.
April 29: Yuan Mu, then spokesman of the State Council, meets with representatives of protest students.
May 5: Party chief Zhao Ziyang expresses sympathy over widespread student dissatisfaction with "corruption and Communist Party mistakes".
May 13: Some student protesters begin week-long pro-democracy hunger strikes to coincide with Soviet President Mikhail Gorbachev's visit to Beijing.
May 15: Gorbachev arrives in Beijing.
May 18: Premier Li Peng, for the first time, meets with representatives from student protesters. However, the two sides fail to achieve results.
May 19: Zhao visits Tiananmen Square, begging students to leave the square. It is Zhao's last public appearance. His top aide Wen Jiabao is at his side in the meeting.
May 20: Li declares martial law.
May 23: More than 100,000 people march in Beijing to demand Li's removal.
May 29: The number in the square falls to 2,000 tired and hungry students.
May 30: "The Goddess of Democracy", a 10-metre replica of the Statue of Liberty, is unveiled in the square.
June 2: Taiwanese singer Hou Dejian, mainland intellectuals Liu Xiaobo, Zhou Duo and Gao Xin announce a two-day hunger strike.
June 3: State-run television warns residents to stay indoors, but crowds of people continue to take to the streets.