Tiananmen Square anniversary: 'I served 17 years for arson'
3 June 2014 Last updated at 01:57 BST
Twenty-five years ago, Tiananmen Square in central Beijing was the scene of pro-democracy demonstrations.
Crowds of protesters, including students and factory workers, had been camped out in the square for weeks before Chinese security services made their move on 4 June 1989.
Estimates of the death toll range from several hundred to several thousand and 1,600 others were arrested. Many were released quickly.
But some have spent most of the past couple of decades in jail.
Dong Shengkun was a labourer in 1989. After being convicted of arson, he spent 17 years in prison.
He spoke to BBC News about his memories of 1989 and the importance of remembering why the protests happened.
Video journalist: Wang Xiqing