International Workers' Day
International Workers’ Day, often referred to as May Day, is a celebration of laborers and the working classes that is promoted by the international labor movement and occurs every year on May 1. The date had been chosen by the American Federation of Labor to continue an earlier campaign for the eight-hour day in the United States, which had been the cause of a general strike beginning on 1 May 1886, and culminated in the Haymarket affair, which occurred in Chicago four days later. May Day subsequently became an annual event.