For almost 2 months in 1989 tens of thousands of protesters led by university students occupied Tiananmen Square in Beijing. The protests were triggered by the death of Hu Yaobang, a former Communist Party General Secretary who was forced to resign for his positions on reforming the party . The students were also demonstrating against corruption in the government, for workers’ rights, and for freedom of speech and the press. On June 3, 1989 the Chinese government ordered martial law and cracked down on the protesters in Tiananmen Square, killing an unknown amount (estimates range from the hundreds to thousands). Here’s an article about some survivors from yesterday’s Washington Post.
At the time I was living and working in Los Angeles. I can still remember sitting at my drawing desk at home when the news started broadcasting those horrifying images from Beijing. 
Associated Press