13 Photos of the Tiananmen Square Massacre That China Doesn't Want the World to See

A bloody crackdown shook the world 25 years ago when Chinese security forces cleared out Tiananmen Square of student protesters during the early hours of the morning of June 4, 1989.

Reporting from Beijing at the time, New York Times journalist Nick Kristof described the bloody scene, where "tens of thousands" of troops stormed the square, in the process reclaiming it from the pro-democracy protesters, killing "scores of students and workers and wounding hundreds more as they fired submachine guns at crowds of people who tried to resist."

The protests first began in April 1989, with students filling Beijing's large, central square, to peacefully call for reform. The weeks that followed saw the arrest of thousands, violent clashes between student protesters and security forces and a disputed death toll, which was estimated to be between 500 and 2,600.

While the iconic image of an unarmed man standing before a row of tanks on a road leading to Tiananmen Square stays firmly planted in the world's collective memory, Chinese authorities have gone to great lengths to scrub the protests, the massacre and that scene from its history. 

Days before the anniversary, Beijing police arrested Pu Zhiqiang, a well-known rights lawyer who has defended renowned artist Ai Weiwei, in order to discourage protests in honor of the massacre's anniversary.

That chill, of course, extends to the Internet. In the time leading up to the massacre's anniversary, the country's censors are hard at work. According to Oiwan Lamat of Global Voices, "The most frequently used and censored term on China's web is 'June 4,' the day the massacre took place. A number of other terms, like 'Hu Yaobang,' 'narrow,' 'rejected' and 'Mirror Magazine,' all of which are associated with the memoir of Deng Liqun on Hu Yuibang, have also been deleted. Keywords related to Hong Kong's politics are also being blocked."

While the exact details of the massacre are disputed, there is no doubt that the tragedy is surrounded by many unanswered questions.

Here are 13 photos of the protests and massacre that rocked China a quarter of a century ago:

1. Tens of thousands of people gather near Martyr's monument in Tiananmen Square, April 21, 1989.

2. Student protesters stand face-to-face with security forces on April 22, 1989.

3. Wang Dan, a Chinese dissident, addresses his fellow students during protests in May 1989.

4. Thousands of students marched towards Tiananmen Square on May 4, 1989.

5. A crowd gathers to burn copies of state-run newspaper Beijing Daily in front of its offices for articles against the student protests on June 2, 1989.

6. A woman gets caught between protesters and soldiers trying to pull her away from the demonstrations on June 3, 1989.

7. Protesters stand atop of a government vehicle while carrying rocks near Chang'an Boulevard on June 4, 1989.

8. Bodies of dead protesters and destroyed bicycles filled Tiananmen Square on June 4, 1989.

9. Many student protesters went on hunger strike during the protests. Here, students sleep in Tiananmen Square on May 14, 1989.

10. A student on hunger strike receives medical attention on May 17, 1989.

11. Troops march down Chanan Blvd, which leads to Tiananmen Square, and fire indiscriminately shots to clear out protesters.

12. Tanks gather in Beijing's center on June 5, 1989.

13. Protesters in Beijing hold up photos of victims killed the day before, during the massacre on June 4, 1989.