1069
Student protesters dancing at Tiananmen Square before the massacre, Beijing, China, 1989
(lemmy.world)
https://en.wikipedia.org/wiki/1989_Tiananmen_Square_protests_and_massacre
The protests lasted over a month; the massacre ended them in a flood of state-sponsored murder.
In the 90s, I found a second-hand book published in English by the PRC (can't remember which ministry) giving the then-official line: that the brave soldiers of the PLA resolutely faced down the forces of a foolhardy counter-revolution and saved Socialism.
Only later came the complete memory-holing.