5.1劳动节又称“五一国际劳动节”源于美国芝加哥城工人大罢工。1886年5月1日，芝加哥的二十一万六千余名工人为争取实行八小时工作制而举行大罢工，经过艰苦的流血斗争，终于获得了胜利。

为纪念这次伟大的工人运动，1889年7月第二国际宣布将五月一日定为国际劳动节。

[翻译]   May Day originated from the workers' strike in Chicago. On May 1, 1886, Chicago's 216,000 workers for the implementation of the eight-hour work system and held a general strike, after a hard bloody struggle, finally won the victory. 

In honor of the great labor movement, the second international labor day was proclaimed in July 1889.