政治示威: This term refers to political demonstrations or protests where people gather publicly to express their opinions or demands regarding political issues.
六四事件: Also known as the June Fourth Incident or Tiananmen Square Massacre, this term refers to the pro-democracy protests in 1989 that took place in Tiananmen Square and resulted in a violent crackdown by the Chinese government.
纪念碑: This term means monument or memorial, and it can refer to the various monuments and memorials located within Tiananmen Square.