In 1886, the organziation that would become the American Federation of Labor (AFL), set out to help workers across the United States to gain better working conditions. They set May 1 as the date for a nationwide strike. Workers across the country, including in cities like Chicago, IL, would go on strike for an 8-hour work day. It wasn't uncommon in 1886 to work more than 16 hours in a day. The May 1 strike worked, and workers across the country would strike for days. Unfortunately that strike would turn deadly and years later workers would call for May 1 to be remembered as Labour Day. 

Learn more about the United States role in International Workers Day by clicking here: NPR: May Day in America