Over a century ago the American Federation of Labour adopted a historic resolution which asserted that "eight hours shall constitute a legal days labour from and after May 1st, 1886".
As you might have guessed, this wasn't written by an American. In America, where Mayday got its start, Mayday and the Chicago martyrs are deliberately ignored. One Utah TV News show proclaimed that in America, Mayday is not honored by marches for workers rights--it is a day for reflecting on good work habits.
http://www.spunk.org/library/intro/sp001497/mayday.html
Just a little history note from a history buff.