Loyalty Day is observed in the USA on May 1, commemorating the reaffirmation of loyalty to the nation and recognizing American freedom. Established in 1921, it was initially called Americanization Day and aimed to replace International Workers' Day, which was associated with Communist and Socialist movements. The holiday marks the events of May 4, 1886, when a bombing occurred during a labor demonstration at Haymarket Square in Chicago. Loyalty Day was officially recognized by the U.S. Congress on April 27, 1955, and was first celebrated as an official holiday in 1959. Celebrations may include parades and ceremonies in some states, although many people remain unaware of the holiday, as it does not have federal status.