Ask the average American to describe May Day and they might mention a pole wrapped in ribbons and springtime pagan rituals. It's true that May 1 does have associations with those things in the Northern Hemisphere, but the holiday has held a greater meaning ever since the Second Industrial Revolution at the end of the 19th century. That's when the International Socialist Conference declared May 1 International Workers’ Day, according to MSN.

May Day evolved from a day reserved for spring festivals to a communist day of remembrance when U.S. workers took to the streets in Chicago 130 years ago. That date was May 1, 1886, and factory workers were fed up with working up to 16-hour days under dangerous conditions. They went on strike to demand more reasonable workday hours until protests erupted in violence. On May 3, several workers were injured or killed in a clash with police, and the following night a bomb detonated in a crowd of police officers monitoring an assembly in Haymarket Square. Police responded by opening fire at protestors, killing several and injuring 200.

Today, socialists and supporters of workers' rights commemorate the incident, known as the Haymarket Affair, each year on May 1. Signs of it are easy to miss in the U.S., but in other countries it's a public holiday that takes the place of Labor Day. Activists around the world often plan marches and protests for the first of May.

The date's modern connotations haven't erased its original significance as an ancient spring festival. Since emerging from pagan traditions, May Day has grown into a secular holiday in Europe, with celebrations including cake, music, and, of course, a dance around the Maypole.

[h/t MSN]

This story was updated in 2019.