Correct answer: the deaths of many protesters.
In response to student-led protests calling for democratic reforms, the Chinese government cracked down harshly. Martial law was declared and over 200,000 troops were deployed to Bejing. On the evening of June 3, 1989, the army opened fire on the protesters, and forceful efforts by the military to clear Tienanmen Square of protesters continued through June 4.
The death toll for protesters has been much disputed. The official Chinese government estimate said no more than 300 were killed -- and they included soldiers in that number. However, a message from the British ambassador to China, sent at the time of the incidents, estimated the death toll to be at least 10.000. The ambassador's memo, declassified in 2017, described how some protesters were bayoneted as they begged for their lives and how human remains were “hosed down the drains.”
After protests in Tienanmen Square in China were crushed, on the next day (June 5), a lone protester stood in the street against the government's tanks. "Tank Man" (as he became known) captured the international imagination as an individual standing up against the overwhelming power of the government.
