Historical events on March 18.

Duan government shot and killed the petitioners. 1926 March 18, more than 5,000 people from more than 60 organizations and more than 80 schools, including the Northern Party Department of the Communist Party of China, the Northern Party Department of the Beijing Communist Youth League, the Beijing Special Committee of the Kuomintang, the Beijing Federation of Trade Unions, the Beijing Federation of Students, the Beijing Anti-imperialist League and the Guangzhou delegation, held an "anti-Eight-Power ultimatum" activity in Tiananmen Square. For the convening of this conference, the Central North District Committee made arrangements and arrangements in advance. On the morning of the same day, Xiao, secretary of Tuanbei District Committee, and Liu Bozhuang, secretary of Tuanbei District Committee, respectively reported on organizing and mobilizing the masses, drawing up slogans and marching routes. The mass meeting began on 10 in the morning. First, the chairman of the meeting, Xu Qian, reported the agenda of the meeting, exposing the imperialist aggression crimes and atrocities committed by the Duan government on 17. The big meeting decided: electrify the whole country to unanimously oppose the ultimatum of the eight countries, expel the ministers of the eight countries, abolish all unequal treaties, and withdraw foreign warships; Telegraph the national army to fight imperialist aggression. After the meeting, the masses marched to the Duan government to petition, demanding that the Duan government immediately refute the eight-nation ultimatum. When the procession came to the front of the executive government in Tieshi Hutong, the crouching military police opened fire, killing 47 people and injuring more than 200 people, creating a "March 18th" tragedy that shocked China and foreign countries. Li Dazhao, Chen Qiaonian, Zhao Shiyan and others from the Northern District Party Committee personally took part in this struggle. Li Dazhao and Chen Qiaonian were injured for covering the crowd. After the tragedy, schools in Beijing were closed to hold a memorial service for the martyrs who died. On 23rd, the Third Hospital of Peking University held a city-wide memorial service under the auspices of Chen Yi. Lu Xun called March 18 "the darkest day since the Republic of China". Since then, Beijing's reactionary rule has become more rampant, Li Dazhao and others have been wanted, and the party's activities have become more difficult.