may 1st - labor/international workers' day (dia do trabalhador) traces its history back to the socialist movements at the turn of the 20th century.

around the world workers were uniting to protest working conditions, low pay, long hours and other inequities.

the day was selected to commemorate the haymarket riots which had occurred in chicago in 1886 and started out as a peaceful demonstration but ended with the killing of both protestors and police officers.

in brazil the day marks the increase of wages for workers and since the day is a floating holiday, meaning it can occur any day of the week, when falling on thursday means that most brazilians will also have the friday off and a four day weekend.