International Workers' Day (May 1, Gregorian) was first observed on May 1, 1890, in many countries around the world. This date was officially designated in the Gregorian calendar following a decision by the Second International Workers’ Congress in Paris in 1889, to commemorate the Chicago workers’ protests of 1886 and their efforts to secure an eight-hour workday. Thousands of workers participated in these protests, demanding shorter working hours. The events included large demonstrations in various cities and, in some cases, violent clashes between workers and police. In Chicago, the Haymarket affair resulted in deaths and injuries among both workers and police officers. These incidents had a significant impact on labor movements globally and became a symbol of the struggle for workers’ rights. Since then, May 1 has been marked annually in many countries as International Workers’ Day. The day is typically observed with marches, gatherings, and events highlighting workers’ demands and emphasizing labor rights. In some countries, it is a public holiday and serves as an occasion to recognize the important role of workers in society.