Thousands of protesters marched in central Hong Kong on Sunday as a part of annual demonstrations demanding that China be held accountable for the 1989 Tiananmen square Massacre.

The Tiananmen crackdown is a taboo subject in China with Chinese internet companies increasingly blocking content related to the event’s 30th anniversary.

The leader of the Hong Kong democratic party said China has tried and erase these memories but the Hong Kong people have not forgotten.