In the late 1800s, workers in parts of the US began campaigning against harsh working conditions.
Back then, 16-hour days in unsafe environments were common.
In May 1886, huge strikes gripped the city of Chicago.
Thousands of workers took to the streets to demand an 8-hour working day.
Protests were repressed by police in what became known as the Haymarket Affair.
7 union leaders were convicted of conspiracy. 4 were later executed.
The Haymarket Affair marked the start of a shift in labour relations in the US.
The 8-hour day was adopted in the printing, construction and railway industries in the early 1900s.
It eventually became law across the US in 1937.
May 1st is now a national holiday in 66 countries.
It’s a day to remember the struggles for dignity and justice at work that have gone before.
And that the fight to improve the lives of working people continues today.
Want to hear about our latest news and blogs?
Sign up now to get it straight to your inbox