“What happened at Tiananmen Square?” could be deflected from a Chinese point of view because that place has existed roughly the way it is since 1420, Mao Zhedong announced the formation of the current regime there, etc. Lots of things have happened there, some of which the current regime is proud of, and some of which it may or may not be depending on how the winds are blowing
https://en.wikipedia.org/wiki/May_Fourth_Movement
https://en.wikipedia.org/wiki/1976_Tiananmen_incident
it's where Chinese people have always gathered in large crowds.