Why was this day designated as International Workers' Day? This goes back to the labor movement in the United States during the 1880s.

At that time, many countries in the United States and Europe gradually developed from capitalism to imperialism. In order to stimulate rapid economic development, they extracted more surplus value to maintain this rapidly running capitalist machine. Capitalists continuously adopted methods of increasing working hours and intensity to cruelly exploit workers.

In the United States, workers had to work 14 to 16 hours a day, and some even as long as 18 hours, but their wages were very low. A supervisor in a shoe factory in Massachusetts once said: "Let a strong and healthy 18-year-old young man work next to any machine here, and I can make his hair turn gray by the age of 22." Heavy class oppression stirred up great anger among the proletariat. They knew that to fight for the conditions of survival, they had to unite and struggle against the capitalists through strikes. The strike slogan proposed by the workers was to demand an eight-hour workday.

In 1877, the first nationwide strike in American history began. The working class marched on the streets, demonstrating and petitioning the government to improve labor and living conditions, to shorten working hours and implement an eight-hour workday. Soon after the strike started, the number of participants increased rapidly, union membership grew, and workers from all over the country also joined the strike movement.

Under the strong pressure of the workers' movement, the U.S. Congress was forced to enact a law for an eight-hour workday. However, the ruthless capitalists ignored it, and this law was nothing more than a piece of paper. Workers still lived in agony and suffered greatly from the exploitation of the capitalists. Unable to bear it any longer, workers decided to push the struggle for the right to survive to a new high, preparing for a larger-scale strike.

In October 1884, eight international and national worker organizations from the United States and Canada held a meeting in Chicago, deciding to hold a general strike on May 1, 1886, forcing the capitalists to implement an eight-hour workday. That day finally arrived. On May 1, more than 20,000 enterprises across the United States saw 350,000 workers go on strike and march in large demonstrations. Workers of various skin colors and trades gathered together for a general strike. In just Chicago, 45,000 workers took to the streets. As a result, the main industrial sectors of the United States were paralyzed. Trains became like snakes, stores fell silent, and all warehouses closed and were sealed. At that time, a song called "Eight Hours" was popular among the striking workers, which sang:

"We want to change the world, we are tired of hard work without getting enough to live on. We have no time to think. We want to smell the flowers, we want to bask in the sun. We believe: God only allows an eight-hour workday. We have gathered our forces from shipyards, workshops, and factories, fighting for eight hours of work, eight hours of rest, and eight hours for ourselves!"