From Wiki80s.org

In 1989, students lead weeks of protests in Beijing's Tiananmen Square, calling for democracy and free speech, and protesting corruption. Crowds grow into the hundreds of thousands, and spark protests in other cities. On June 4, after martial law is declared in Beijing, the military moves in to crush the protests, killing hundreds.

Here a lone protester faces off with tanks and is probably the most remembered scene of the Tiananmen Square protests. Several years of renewed political repression follow the crackdown and economic reforms stall. Many activists are jailed or flee the country. Party Secretary Zhao Ziyang, accused of using the protests to make a power play, is put under house arrest, where he ramains until he dies in 2005.

Story source: msnbc