The demonstrations hit an apex on 15 May with the arrival of Soviet President Mikhail Gorbachev, whose sweeping reforms to open up Russia's Communist system would prove to be its undoing.
Perhaps mindful of such dangers, hard-liners in Beijing took a different approach. They canceled their plans to meet Gorbachev in Tiananmen Square and declared martial law a few days later.
Then, shortly after midnight on 4 June, the Communist government sent in thousands of troops -- including tanks and armored personnel carriers -- to forcibly reclaim Tiananmen Square from the students.
As the troops moved into the square, American John King watched from a block or two away. Then a university student in Beijing, King's courses had been canceled due to the rallies but he had stayed on to work as a news production assistant for the U.S. national television network ABC.
"You were seeing at that point military shooting all over. And I ran to a student, a classmate wearing a white shirt. He had a spout of arterial spray on the left side of him and a spout of arterial spray on the right side of him. And I guess he was standing there on the square or near it, and had literally the two people on either side of him catch bullets and go down. And he was wearing this white shirt with the remains of these guys on either side of him," King said.
Controversy still surrounds the question of just how many people died that night. Some claim as many as several thousand protesters perished. Others say the figure was actually far lower. What remains clear is that hopes for imminent political reform did not survive the storming of the square.
But while the hard-liners clamped down, they knew the survival of their regime would require drastic measures.
Minxin Pei is a Chinese-born, Harvard-educated scholar with Washington's Carnegie Endowment for International Peace. He tells RFE/RL that as a result of the protests of spring 1989, China's Communists were forced to launch liberal economic reforms partly to ensure their own survival.
As a result of those reforms, China's economic and social life have been transformed to such an extent that 15 years after Tiananmen Square, China is hardly recognizable.
"China today is a different country. China today is much more open as a society. China today is much more prosperous. And China today is much more diverse. However, the Chinese political system has basically remained unchanged. The Communist Party continues to maintain its political monopoly and it has also maintained the same policy of trying to keep the economy going but keep the political system closed," Minxin said.
In sheer numbers, China's economic transformation is staggering.
Long the world's most populous country with more than 1 billion people, China now ranks second in the world in terms of economic power.
Last year, Beijing accounted for 16 percent of world economic growth, second only to the United States. Its economy has grown at an annual rate of some 10 percent for several years. Since 1990, it has attracted $500 billion in foreign investment. Total exports have grown eightfold and its share of global exports reached 6 percent in 2003, compared to 3.9 percent in 2000.
China has gone from being a producer of low-quality exports to sophisticated high-tech goods. The greatest beneficiaries, says Minxin, have been educated urban dwellers.
"In 1989, very few people owned their houses. No private citizens owned their cars; and today you can find lots of them. The standard of living for the urban population, certainly, has quadrupled in the last 15 years, measured in terms of income and consumption," Minxin said.
But there has also been a price to pay for the reforms. Farmers toil under a massive tax burden and many live in dire poverty. And as living standards overall have improved, workers for uncompetitive state firms that have gone bankrupt account for a huge surge in inequality, Minxin says.
"Almost 40 million people have lost their jobs. As a result, about 25 million people at a minimum in urban areas have fallen into poverty. In a nutshell, inequality in the last 15 years has grown up tremendously, probably by 50 percent," Minxin said.
Meanwhile, the time bomb at the heart of Chinese society remains its closed political system and continued human rights abuse.
Minxin says that major "signature events" such as the Tiananmen Square uprising may get a lot of attention in the West, but the more important daily abuse of human rights in China -- from torture to police brutality to corruption at all levels -- unfortunately goes largely unnoticed.
In liberalizing the economy, Communist authorities have had to give up some of their control over peoples' lives. But experts say that if the government is to avoid an eventual economic crash, it will need to push for further economic reforms, such as fostering mature and independent capital markets. But that, they say, would mean relinquishing even more control.
That would seem to suggest that political reform is an inevitable development after a period of massive economic growth under one-party rule.
Wang Dan, one of the leaders of the 1989 uprising, argued this week in "The Wall Street Journal" that democracy will eventually come in China from the bottom up, as people with a taste of freedom will eventually demand more.
Statistics appear to support this theory. Far from dying out since 1989, protests in China have been growing strong, according to Murray Scott Turner of the Rand Corporation, a U.S. think tank.
Citing official Chinese police statistics, Turner says that the number of demonstrations increased from 8,700 in 1993 to 32,000 in 1999. He says that number is once again on the rise after peaking during the financial crises of 1997 and 1998.
King, the former U.S. student of Chinese history who witnessed the events in Tiananmen Square, says he believes a repeat scenario is entirely possible:
"If it happened tomorrow all over again, in the same scale, people demanding greater freedoms -- it wouldn't surprise me at all," King said.
But the Rand Corporation's Turner says the Chinese authorities now appear much less likely to resort to violence to stop popular protests and that police often recognize that demonstrators are motivated by legitimate grievances, such as rapacious managers and corrupt local officials.
Meanwhile, China's newest leader, Hu Jintao, has shown an apparent willingness to listen to critics, organizing monthly meetings with intellectuals and experts on everything from the fall of great powers to global economics and constitutional law.
Still, Minxin says China's leadership is unlikely to pursue political reforms.
Fifteen years later, the government still acknowledges no responsibility for Tiananmen Square and recently made senior officials view a documentary that argues that crushing the uprising was necessary. The government also shows growing signs of intolerance of political openness in Hong Kong.
After Beijing warned it would not permit full democracy any time soon in the former British colony, residents protested last week. One of them told Reuters that she was also protesting the dead of Tiananmen Square:
"I have come here every year and I will continue to come so long as the [democracy] movement is not vindicated. So many people have died and their lives must be remembered," the protester said.
Meanwhile, one thing that could eventually spark political change across China is money.
Minxin says that in the event of major economic crisis, China's leadership would be forced to reform because their strategy of one-party rule would be shown to be bankrupt.