For the massacre’s victims, and for those whom an increasingly aggressive, totalitarian Beijing would victimize in the future, we must remember June 4, 1989.

This week, China will diverge from the rest of the world as if it resides in an alternate universe. While outside of China the world will commemorate the 30th anniversary of the Tiananmen Square Massacre that took place on June 4th, 1989, inside the country President Xi Jinping’s regime will continue its campaign of silence: not acknowledging the massacre ever took place; not apologizing to victims and their families; strongly condemning any commemorative activities outside China; and deploying its massive cyber-security force to vigorously scrub any mention of the incident from the domestic Internet.

The censorship will be so thorough that Chinese people won’t even be able to send a text message that contains any one of the numbers eight, nine, six, and four. Such a campaign of silence has been going on for 30 years, and as technology has improved, the Chinese government has only gotten better at suppressing dissent.

Fortunately, there is a world outside of China, a world in which good people still want to keep the memory of Tiananmen alive by retelling the story of what happened there, much to the Chinese government’s annoyance.

I was in China in the 80s when this story unfolded. Looking back, 1986 to 1989 was probably the most liberal period in the country’s history since the Communist Party assumed power in 1949. Besides economic reform, Hu Yaobang, the most liberal-minded party leader China ever had, wanted to bring a level of transparency to the totalitarian state, which angered his political opponents. He was purged from his post as party secretary in 1987 and disappeared from the public eye, replaced by Zhao Ziyang, who turned out to be similarly reform-minded.

Two years later, in April 1989, Hu passed away. Coincidentally, he died right around the traditional Qingming holiday, when people pay tribute to their deceased loved ones. Many ordinary Chinese people took to the street to pay tribute to Hu. Gradually, mourning for Hu turned into a movement calling on the Chinese government to grant citizens more freedom and apply meaningful anticorruption measures. Peaceful demonstrators, mostly students, started occupying Beijing’s Tiananmen Square.

During the early stages of the movement, the central government under Secretary Zhao showed a certain level of tolerance. China Central TV produced relatively fair coverage of the protestors’ daily activities. Students from the Central Art Institute built a Chinese version of the Statue of Liberty in the middle of the square. They also read out a translated version of America’s Declaration of Independence. Like millions of other Chinese people, I first heard these magnificent words then: “We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.”

These principles were very different from those we were used to hearing from the party. Under Mao Zedong and his Communist cadres, Chinese people had lived in a society where the state made decisions regarding how much food one could have, what one could wear, what one could study, whom one should work for, which social class one belonged to, and even what thoughts one should have. The reforms of the 1980s had brought Chinese people some economic relief, but their basic relationship with the state hadn’t changed.

Hearing students read America’s Declaration of Independence out loud on TV awakened something deep in people’s souls. Throughout China, from big cities to small towns, more and more people, especially students, took to the streets to support the student protesters in Beijing and demand more meaningful political reform. Ordinary citizens voluntarily donated money and food to the protesters. There was a euphoria in the air and everyone was hopeful that some positive political change would happen.

And change did happen, but not the kind people had hoped for. Deng Xiaoping, the paramount leader who controlled the Communist Party and the country, dismissed Zhao as party secretary, believing he was too “soft” and had lost control of the situation. After Zhao’s purge, the tone of CCTV’s coverage of the protest movement became very negative. Students in Tiananmen Square were accused of being under a foreign enemy’s influence. Adults such as my parents, who had experienced many of the Communist party’s past political campaigns, sensed something terrible was about to happen.

On the fateful day of June 4, 1989, we woke up to the news that Tiananmen Square had been cleared out, without any official explanation of what had really taken place. In the following days, there were rumors about innocent people being killed in the square, but the government insisted that no one had died. People who participated in the protests were quietly being persecuted. Family and friends whispered that many university students who graduated in the summer of 1989 were sent to work in remote areas as a punishment for their participation in the protests. But the biggest question on the minds of everybody who wasn’t in Beijing on that fateful day was: What truly happened in Tiananmen Square?

Only later, when I came to the U.S., did I learn the answer: Armed troops had fired indiscriminately on crowds made up of unarmed students and civilians. I saw photos, including the famous image of the Tank Man, a lone figure standing in front of rows of tanks. I read eyewitness accounts and news reports, and learned the estimated death toll was in the thousands. Thousands more were persecuted afterward. I was shocked and felt sick to my stomach.

Yet compared to most Chinese people, I was lucky: Safely outside the country, I got to know the truth. Since 1989, June 4th has become the most sensitive subject inside China. Any reference to that day, the movement, or its key players will cause serious trouble. As Louisa Lam, longtime journalist and the author of The People’s Republic of Amnesia, explains, the Chinese government relentlessly suppresses any commemoration of June 4th because even “a single act of public remembrance might expose the frailty of the state’s carefully constructed edifice of accepted history, scaffolded in place over a generation and kept aloft by a brittle structure of strict censorship, blatant falsehood and willful forgetting.”

VIEW SLIDESHOW: Tiananmen Square Protests

In addition to its successful campaign of silence, the party has spent a great deal of effort rewriting the history of that period to its advantage. It has been so successful that generations of Chinese who’ve grown up since the massacre have never even heard of it. Here’s Lam, describing an experiment she did in China:

I took the iconic picture of Tank Man to four Beijing campuses. Out of 100 students, only 15 could identify the picture. The others leaned in, eager and wide-eyed, asking: “Is it from South Korea?” and “Is it in Kosovo?” One young woman asked what I was writing about. I answered directly: “About liu si [June fourth].” She looked blank. “What is that?” she asked. “I don’t know what that means.”

Professor Rowena He, who participated in the Tiananmen protests as a college student in 1989 and now teaches a freshman seminar on the movement at Harvard, often encounters students from mainland China who have never heard of the Tiananmen Massacre. Some of these students are willing to open their mind. But others turn away from mountains of evidence, attacking her as a traitor for exposing such a dark chapter of China’s history on foreign soil.

Even many in the older generation that lived through 1989 choose to either willfully forget about it or accept the government-sanctioned narrative that the massacre was a lie fabricated by China’s Western enemies. When presented with evidence, some of them, including Alibaba founder Jack Ma, have said that any crackdown on the students was necessary for China’s security and prosperity.

“The best prophet of the future is the past,” Lord Byron once wrote. Since the party is unwilling to tell the truth and the rest of the world has given it a pass for 30 years, lured into silence by the country’s massive consumer market, today’s Chinese state is more repressive than it was in 1989. More than one million Chinese Muslim Uighurs are locked up in re-education camps. The rest of them live under constant high-tech surveillance. Despite international outcry, the government refuses to let those innocents go. Instead, it insists that Uighurs behind bars are “voluntarily” accepting its offer of “vocational training.”

The legacy of Tiananmen goes beyond ongoing human-rights abuses. In professor He’s words, “The distortion of history is accompanied by distortions of all kinds — political, social, psychological. Such values, stopping at nothing for its goals, have not only affected China, but the world.” From the South China Sea to President Xi’s massive “Belt and Road” initiative, all of us are already living in a world distorted by an increasingly powerful and authoritatarian China. Only speaking the truth can break such distortion. This is why we must keep talking about what really happened in Tiananmen: for the heroes who perished 30 years ago, and for the freedom of future generations.