What is International Worker's or May Day? The Bloody Story

The 1 May date is now most commonly associated as a commemoration of the achievements of the labour movement. But 1 May is celebrated as May Day in most countries around the world as an ancient spring festival. In the United Kingdom and Ireland the bank holiday isn't fixed on May 1st, but instead is observed on the first Monday of May.

The holiday may also be known as Labour Day or International Worker's Day and is marked with a public holiday in over 80 countries, but there is a bloody story of how May Day became a Holiday for Workers. The 1 May date is used because in 1884 the American Federation of Organized Trades Unions demanded an eight-hour workday, to come in effect as of 1 May 1886. This resulted in the general strike and the Haymarket Riot of 1886, a bomb exploded in the police ranks. It wounded 67 policemen, of whom seven died. The police opened fire, killing several men and wounding 200, and the Haymarket Tragedy became a part of U. S. history.

http://www.officeholidays.com/countries/global/may_day.php
http://time.com/3836834/may-day-labor-history/
https://en.wikipedia.org/wiki/International_Workers%27_Day
http://aattp.org/read-the-real-bloody-and-amazing-story-of-labor-day/