Tiananmen Square is located in the center of Beijing, the capital of China.
In 1989, after several weeks of demonstrations, Chinese troops entered Tiananmen Square on June 4 and fired on civilians.
Estimates of the death toll range from several hundred to thousands. It has been estimated that as many as 10,000 people were arrested during and after the protests. Several dozen people have been executed for their parts in the demonstrations.
http://time.com/2822290/tiananmen-square-massacre-facts-time/
http://edition.cnn.com/2013/09/15/world/asia/tiananmen-square-fast-facts/