Why did the Chinese government want to keep the events at Tiananmen Square a secret

The Tiananmen Square protests were student-led demonstrations calling for democracy, free speech and a free press in China. They were halted in a bloody crackdown, known as the Tiananmen Square Massacre, by the Chinese government on June 4 and 5, 1989.

Pro-democracy protesters, mostly students, initially marched through Beijing to Tiananmen Square following the death of Hu Yaobang. Hu, a former Communist Party leader, had worked to introduce democratic reform in China. In mourning Hu, the students called for a more open, democratic government. Eventually thousands of people joined the students in Tiananmen Square, with the protest's numbers increasing to the tens of thousands by mid-May.