On this day, 98 years ago, on March 24, 1927 (February 21, 1927, the United States and the United States committed the "March 24th" tragedy in Nanjing. On March 24, 1927, British and American warships bombarded Nanjing. This was one of the crimes of imperialist interference in China's revolution during the Northern Expedition. When the Northern Expedition Army marched towards the lower reaches of the Yangtze River in 1927, the United States, Britain, France, Italy, Japan and other countries sent more troops to Shanghai and mobilized warships to threaten the Nanjing River in an attempt to stop the development of the revolution. On March 24, the Sixth and Second Armies of the National Revolutionary Army under Cheng Qian's command, led and fought by Communists, invaded Nanjing after defeating hundreds of thousands of enemy troops. That night, the British and American imperialists, on the pretext that their expatriates and consulates were being "invaded by thugs," ordered shelling of Nanjing, killing and injuring more than 2000 China soldiers and civilians, damaging countless houses and property, resulting in a large-scale bloody case. After the incident, the United States, the United States and other countries continued to send more troops to China, but also made unreasonable demands on China such as punishment of criminals, wanted fugitives, and compensation. On March 30, 1928, Chiang Kai-shek sent special envoys to Nanjing to communicate with the consuls of various countries to express his apology and compensation to the imperialists, and ordered an arrest for the shooting of Li Fuchun and Lin Boqu to "apologize". This incident was a signal that imperialist armed forces interfered in China's revolution, and it was also an important step for Chiang Kai-shek to accelerate collusion with imperialism and betray the revolution.