The first day of May has, since 1891, been celebrated as the International Worker's Day in commemoration of the labour and the working classes who provide invaluable work all over the world. It is only in about 80 countries that Labor day is celebrated on the 1st of may while many countries celebrate it according to their own labor movements.
This is one day that has been marked by the government as a public holiday and is celebrated all over the world with much ado.