China allows no public discussion of the events of June 3 and 4 1989, when soldiers backed by tanks and armoured personnel carriers fought their way into the heart of the city, killing hundreds of unarmed protesters and onlookers.
The government has never issued a complete, formal accounting of the crackdown or the number of casualties.
More top news
Mother of Bobby and Christi Shepherd says Thomas Cook apology was 'too little too late' as she calls for greater safety standards.
The Neverland ranch where pop star Michael Jackson lived until running into financial difficulties has been put up for sale.
A 43rd generation direct descendant of the Prophet Muhammad, the Prince has vowed to clean up Fifa's act.