What happened
Student-led protests calling for political reform, freedom of the press, and an end to corruption had grown to occupy Tiananmen Square for weeks, drawing sympathetic crowds from across Beijing and inspiring solidarity protests in cities nationwide. Deng Xiaoping, then China's paramount leader in all but formal title, made the decision to declare martial law and ultimately to use the military against the demonstrators.
On the night of 3–4 June, PLA units advanced into central Beijing along Chang'an Avenue, opening fire on protesters and bystanders attempting to block their advance. The Chinese government's own internal count reported to the Politburo shortly afterward put the toll at 241 dead, including 218 civilians; contemporaneous Western reporting and Amnesty International estimates ranged from several hundred to close to a thousand civilian deaths, with a disputed British diplomatic cable claiming a toll as high as 10,000 — a figure most historians treat with scepticism but which illustrates how uncertain the true count remains.
The Tiananmen Mothers, a victims' advocacy group founded by parents of those killed, have documented 202 individual victims by name as of 2011 — a fraction of even the lowest death toll estimates, illustrating how thoroughly the state has prevented independent verification in the decades since. Discussion of the massacre remains censored inside China to this day, and the anniversary is marked by heightened surveillance and detention of activists rather than any official commemoration.