Mayday
Day of international resistance and solidarity against capitalism.

Originally a day of carnivalesque suspension of the social order of work and control, prevalent among peasant communities in mediaeval Europe.  A continuation of earlier pagan festivities which continued in a syncretic way during the Christian era, with rituals such as the maypole retained.  (This was originally a pagan fertility ritual).

It became a focus of international resistance for two reasons: firstly, because the campaign for Mayday to be made into a holiday was an important early campaign of the workers' movement, and secondly and more importantly, because of the Haymarket martyrs, anarchists stitched up over a bombing at a protest.
It has become an important focal point for resistance in recent years in countries such as Britain and Australia, and for a longer time in Germany.  Anarchist, anti-capitalist and direct action events have been organised, as well as left-wing demonstrations and parades.