义和团运动 (Yìhétuán Yùndòng), The Boxer Rebellion, was a protest movement that started in 1899, when the Qing Emperor was unable to hold off hostile incursions by Western countries and Japan. To add to the misery, these years also saw severe drought, and the Boxers had had enough.
The “Boxers” were armed militia, so named by Western missionaries (their main targets) for their martial arts aesthetic. When the Chinese government supported the Boxers, the Eight Nation Alliance (six European countries plus the US and Japan) invaded Beijing and forced the government to sign the “Boxer Protocol” in 1901.
The legacy of the Eight Nation Alliance can still be experienced in Beijing, which was plundered excessively: The ruins of the Old Summer Palace are preserved to remind the nation of the time when China was weak and vulnerable. Some of the reparations to the US was repurposed to pay for the now-famous Tsinghua University.
The Alliance attacking Beijing. Picture from a Japanese newspaper, Wikimedia Commons