Post-Mao China and anxieties about the future lead to unrest in China. People began to desire the following things: democracy, freedom of speech, freedom of the press, and other freedoms allowed in other parts of the world.
Bald Eagle (represents freedom)
In 1989, there were student led pro-democracy demonstrations/protests. A majority of the protesters were progressive college students. At the peak of the protests, there were about a million people in Tiananmen Square.
College - Students made up majority of protestors
However, these demonstrations spread across the countries. It was clear that people wanted change. So, the government declared "martial law" which is the imposition of direct military control of normally civilian functions of government.
The government reacted by forcibly stopping the protests. Tanks and troops with guns killed many of the protestors. Unfortunately, an exact estimate is impossible as the Chinese government attempted to cover it up.
After the massacre, the Chinese government arrested journalists, suspected "sympathizers" and officers in the government. They coined the riots as "Counter-Revolutionary."
Even though there was an attempt to cover it up, the information spread across the world. Countries around the world condemned China's actions of suppression.
In fact, many countries set economic sanctions and arms embargoes on China. This affected China's operation or planning of economic/foreign policy on a global basis. In other words, China's globalism was changed.
There actions had ramifications in world relations. It also created a ripple affect across the world questioning the integrity of the communist party. Here is a news report from BBC news after the incident:
Now, in a very censored Chinese country, information about this incident is blocked. The search term "Tiananmen Square" and even the numbers "6, 4, 1989" (to represent June 4, 1989) are banned. So, essentially the facts about this incident have been erased to the Chinese people.