(Minghui.org) Representatives of workers from several European countries gathered at St. Martin's Hall, London in September 1864, and founded the International Workingmen's Association organization, also known as the First International. Among the attendees was Karl Marx, who became an influential member of the new organization. 

Members of the First International took an active part in the Paris Commune in 1871. After the failure of Paris Commune and internal conflicts within the organization, the First International was dissolved in 1876. 

Over 35,000 workers went on strike in Chicago on May 1, 1886, demanding “eight-hour day with no cut in pay.” It led to Haymarket Affair, one of the most significant events in the history of labor in the United States.

In 1889, delegations from twenty countries met in Paris and established the Second International, as a successor to the earlier First International. It called for demonstrations around the world on the anniversary of the Chicago protest. And it adopted a resolution declaring May 1 as International Worker's Day, often referred to as May Day. 

May Day has since become an important holiday celebrated in many communist countries, including China, North Korea, and former Soviet Union countries. For example, large parades, including displays of military hardware and soldiers, were held in Moscow every year during the Soviet era. 

In China, May 1 was first declared as Labor Day in 1949 when the Communist Party took power. In 1999, the government designated the week starting May 1 as Golden Week, a 7-day national holiday, to help expand the domestic tourism market and allow people to make long-distance family visits. However, the number of holiday days has shrunk to three days since 2008. 

In many other countries, labor unions and socialist organizations continue the tradition of May Day by staging rallies and protests. In recent years, the May Day demonstrations by some anarchist groups have led to riots and confrontations with police.