This file photo taken twenty years ago on June 2, 1989 shows some of the hundreds of thousands of Chinese gathering around a 10-meter replica of the Statue of Liberty (center), called the Goddess of Democracy, in Tiananmen Square demanding democracy despite martial law in Beijing. Hundreds, possibly thousands, of protesters were killed by China's military on June 3 and 4, 1989, as communist leaders ordered an end to six weeks of unprecedented democracy protests in the heart of the Chinese capital.

A file photograph from June 3, 1989 shows a dissident student (left) shouting to soldiers, asking them to go back home as crowds flood into central Beijing ahead of the army's crackdown on pro-democracy protests.

This file photo taken on June 4, 1989 shows an armoured personnel carrier in flames as students set it on fire near Tiananmen Square in Beijing.

In this photo taken on June 5, 1989 and made available for the first time by the AP on Thursday June 4, 2009, three unidentified men flee the scene, as another man (background left) stands alone to block a line of approaching tanks (background right) in Beijing's Tiananmen Square. This previously unseen photograph was taken by then-AP reporter Terril Jones and came to light after online discussions of the incident on The New York Times' Lens Blog on the 20th anniversary of the Tiananmen Square crackdown.

A single man blocks an approaching column of PLA tanks on Changan Avenue east of Tiananmen Square in Beijing June 5, 1989.

In this June 5, 1989 file photo, a Chinese protestor blocks a line of tanks heading east on Beijing's Cangan Blvd. June 5, 1989 in front of the Beijing Hotel. The man was shortly pulled away and the tanks continued on their way.