Tiananmen Square in Beijing, located directly to the south of the [[天安门|天安門|tian1 an1 men2]]

The Tiananmen Square Incident of April 5, 1976, which was a protest against the Gang of Four following the death of Zhou Enlai; also refers to the [[四五运动|四五運動|si4 wu3 yun4 dong4]]

(euphemism) a person's pants fly is down; the barn door is open