In late May 1989, thousands of students in Beijing gathered to take advantage of the media exposure that was to follow Soviet President Mikhail Gorbachev’s visit. They found it the perfect opportunity to stage pro-democracy demonstrations and occupied Tiananmen Square for almost a fortnight. The university students were vocal in their demands for reinstating democratic freedoms including freedom of speech and press as well as government accountability. Inspired by the students, about a million people are believed to have assembled.

Deng Xiaoping and other leaders resorted to the use of force. Martial law was declared on May 20, and over 300,000 troops were deployed in Beijing. The demonstrations came to a sordid and violent end on the night of June 3 going into the early hours of June 4. The army launched an assault on the civilians who had blocked the square. These brutal attacks were broadcast live by international news agencies and served to shock the world. While official statements said that no student had been killed in the protest, unofficial news recorded deaths at the Tiananmen Square between hundreds and thousands. A picture of lone demonstrator standing down a column of tanks on June 5, at the entrance to Tiananmen Square became image of pro-democracy demand.

Following the Tiananmen Square massacre, China was severely criticized by the international community and levied economic sanctions. The Communist Party of China has remained unperturbed in the face of all opposition and continued its hardcore policy of snubbing out all dissent and removing all demands for democracy. Since 1989, the Chinese government has gone to great lengths to censor any mention of the Tiananmen Square massacre. Immediately following the incident, news agencies were issued warnings to run only the official account. Images and videos of the Tiananmen Square massacre were destroyed by the Chinese authorities and films which mention the Tiananmen Square massacre are banned in the country. Not many Chinese outside Beijing know the truth of the incident.

Reference:

http://www.mapsofworld.com/on-this-day/june-4-1989-tiananmen-square-massacre-takes-place

http://mashable.com/2014/06/04/tiananmen-square-massacre-photos/