A pivotal moment in the U.S. labor movement is often remembered as the Haymarket Affair, which occurred on May 4, 1886. This event began as a peaceful rally in support of workers striking for an eight-hour workday in Chicago. When a bomb was thrown at the police, resulting in deaths and injuries, it led to widespread unrest and a crackdown on labor protests. The incident became a significant symbol of the struggles faced by labor unions and workers advocating for rights and fair treatment. In the years that followed, the Haymarket Affair contributed to the establishment of International Workers' Day, celebrated worldwide.