May Day in Moscow is still an occasion to honour workers' contribution to society

In the late 19th Century, May Day became associated with the organised labour movement.

This was a time when trade unions were growing in strength and demanding fairer conditions, higher wages and limits on the working day.

In 1889, an international Socialists meeting in Paris voted to make May Day a memorial to the struggle of working people throughout the world.

The date was chosen in honour of four men who died three years earlier trying to further workers' rights in the US.

The US Federation of Organised Trades and Labour Unions had passed a resolution stating that eight hours would constitute a legal day's work from and after 1 May 1886.

But during a mass workers' strike in Chicago on 3 May police fired into the crowd killing four protesters.

Revolutionaries

May Day has evolved into a day of protests

The situation worsened a few days later when a bomb was thrown at police during a demonstration to commemorate the workers' deaths in Chicago's Haymarket Square.

A number of anarchists were later rounded up and, despite a lack of evidence connecting any of them with the bomb, they were found guilty and executed.

For revolutionaries and workers everywhere, Haymarket became a symbol of the struggle for a new world.

May Day became a major holiday in the Soviet Union and other Communist countries.

The traditional workers' holiday, recognised as International Labour Day by the United Nations, has evolved into a day of protests for a raft of political and social causes.